diff --git a/radio/src/datastructs.h b/radio/src/datastructs.h
index 7d9af9f83..c8e8bd3b3 100644
--- a/radio/src/datastructs.h
+++ b/radio/src/datastructs.h
@@ -310,7 +310,7 @@ union TelemetryScreenData {
 #if defined(PCBTARANIS)
   TelemetryScriptData script;
 #endif
-};
+} FUNC(select_tele_screen_data);
 #endif
 
 PACK(struct VarioData {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
index 0aa4bfc21..e3fd62bfc 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
@@ -89,7 +89,7 @@ static bool w_vbat_max(const YamlNode* node, uint32_t val, yaml_writer_func wf,
 }
 
 #if defined(COLORLCD)
-static uint8_t select_zov(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_zov(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     data -= sizeof(ZoneOptionValueEnum);
@@ -100,7 +100,7 @@ static uint8_t select_zov(uint8_t* data, uint32_t bitoffs)
 }
 #endif
 
-static uint8_t select_mod_type(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_mod_type(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     data -= offsetof(ModuleData, ppm);
@@ -136,7 +136,7 @@ static uint8_t select_mod_type(uint8_t* data, uint32_t bitoffs)
     return 0;
 }
 
-static uint8_t select_custom_fn(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_custom_fn(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     data -= offsetof(CustomFunctionData, all);
@@ -154,71 +154,58 @@ static uint8_t select_custom_fn(uint8_t* data, uint32_t bitoffs)
     return 1;
 }
 
-static uint8_t select_script_input(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_script_input(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'value'
     return 0;
 }
 
-static uint8_t select_id1(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_id1(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'id'
     return 0;
 }
 
-static uint8_t select_id2(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_id2(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'instance'
     return 0;
 }
 
-static uint8_t select_sensor_cfg(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_sensor_cfg(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'param'
     return 5;
 }
 
-#if 0
-static uint32_t sw_read(const char* val, uint8_t val_len)
+static bool sw_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    uint32_t sw = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (sw >= MIXSRC_FIRST_SWITCH)
-        return sw - MIXSRC_FIRST_SWITCH;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
 
-    return -1;
-}
-#endif
-
-static bool sw_write(uint32_t idx, yaml_writer_func wf, void* opaque)
-{
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_SWITCH, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  const char* str =
+      yaml_output_enum(idx + MIXSRC_FIRST_SWITCH, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-#if 0
-static void r_stick_name(const YamlNode* node, uint8_t* data,
-                         uint32_t bitoffs, uint16_t idx,
-                         const char* val, uint8_t val_len)
-{
-    data -= offsetof(RadioData, switchConfig);
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
-}
-#endif
-
-static bool w_stick_name(const YamlNode* node, uint8_t* data,
-                         uint32_t bitoffs, uint16_t idx,
+static bool w_stick_name(void* user, uint8_t* data, uint32_t bitoffs,
                          yaml_writer_func wf, void* opaque)
 {
-    data -= offsetof(RadioData, switchConfig);
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    return wf(opaque, rd->anaNames[idx], strnlen(rd->anaNames[idx], LEN_ANA_NAME));
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+
+  data -= offsetof(RadioData, switchConfig);
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  return wf(opaque, rd->anaNames[idx],
+            strnlen(rd->anaNames[idx], LEN_ANA_NAME));
 }
 
-static bool stick_name_valid(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool stick_name_valid(void* user, uint8_t* data, uint32_t bitoffs)
 {
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    return rd->anaNames[idx][0] != '\0';
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  return rd->anaNames[idx][0] != '\0';
 }
 
 static const struct YamlNode struct_sticksConfig[] = {
@@ -227,29 +214,19 @@ static const struct YamlNode struct_sticksConfig[] = {
     YAML_END
 };
 
-#if 0
-static void sw_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                         uint16_t idx, const char* val, uint8_t val_len)
+static bool sw_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                          yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, switchConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    strncpy(rd->switchNames[idx], val, std::min<uint8_t>(val_len, LEN_SWITCH_NAME));
-}
-#endif
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, switchConfig);
 
-static bool sw_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, yaml_writer_func wf, void* opaque)
-{
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, switchConfig);
-
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    const char* str = rd->switchNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_SWITCH_NAME));
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  const char* str = rd->switchNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_SWITCH_NAME));
 }
 
 static const struct YamlIdStr enum_SwitchConfig[] = {
@@ -267,48 +244,29 @@ static const struct YamlNode struct_switchConfig[] = {
     YAML_END
 };
 
-#if 0
-static uint32_t pot_read(const char* val, uint8_t val_len)
+static bool pot_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    uint32_t pot = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (pot >= MIXSRC_FIRST_POT)
-        return pot - MIXSRC_FIRST_POT;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
 
-    return -1;
-}
-#endif
-
-static bool pot_write(uint32_t idx, yaml_writer_func wf, void* opaque)
-{
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_POT, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  const char* str = yaml_output_enum(idx + MIXSRC_FIRST_POT, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-#if 0
-static void pot_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, const char* val, uint8_t val_len)
+static bool pot_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                           yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, potsConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS;
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
-}
-#endif
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, potsConfig);
 
-static bool pot_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                           uint16_t idx, yaml_writer_func wf, void* opaque)
-{
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, potsConfig);
-
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS;
-    const char* str = rd->anaNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS;
+  const char* str = rd->anaNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
 }
 
 static const struct YamlIdStr enum_PotConfig[] = {
@@ -326,66 +284,39 @@ static const struct YamlNode struct_potConfig[] = {
     YAML_END
 };
 
-#if 0
-static uint32_t slider_read(const char* val, uint8_t val_len)
+static bool slider_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    uint32_t sl = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (sl >= MIXSRC_FIRST_SLIDER)
-        return sl - MIXSRC_FIRST_SLIDER;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
 
-    return -1;
-}
-#endif
-
-static bool slider_write(uint32_t idx, yaml_writer_func wf, void* opaque)
-{
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_SLIDER, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  const char* str =
+      yaml_output_enum(idx + MIXSRC_FIRST_SLIDER, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-#if 0
-static void sl_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                         uint16_t idx, const char* val, uint8_t val_len)
+static bool sl_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                          yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+
+  // data / bitoffs already incremented
 #if defined(PCBTARANIS)
-    // Please note:
-    //   slidersConfig is defined as a bit-field member,
-    //   so let's take the next field and subtract 1
-    //
-    data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
-    data -= offsetof(RadioData, potsConfig) - 1;
+  // Please note:
+  //   slidersConfig is defined as a bit-field member,
+  //   so let's take the next field and subtract 1
+  //
+  data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
+  data -= offsetof(RadioData, potsConfig) - 1;
 #else
-    data -= (idx + 1) / 8;
-    data -= offsetof(RadioData, slidersConfig);
+  data -= (idx + 1) / 8;
+  data -= offsetof(RadioData, slidersConfig);
 #endif
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS + STORAGE_NUM_POTS;
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
-}
-#endif
-
-static bool sl_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, yaml_writer_func wf, void* opaque)
-{
-    // data / bitoffs already incremented
-#if defined(PCBTARANIS)
-    // Please note:
-    //   slidersConfig is defined as a bit-field member,
-    //   so let's take the next field and subtract 1
-    //
-    data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
-    data -= offsetof(RadioData, potsConfig) - 1;
-#else
-    data -= (idx + 1) / 8;
-    data -= offsetof(RadioData, slidersConfig);
-#endif
-
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS + STORAGE_NUM_POTS;
-    const char* str = rd->anaNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS + STORAGE_NUM_POTS;
+  const char* str = rd->anaNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
 }
 
 static const struct YamlIdStr enum_SliderConfig[] = {
@@ -456,19 +387,19 @@ static bool w_swtchSrc(const YamlNode* node, uint32_t val, yaml_writer_func wf,
     return wf(opaque, str, strlen(str));
 }
 
-static bool cfn_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool cfn_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     return ((CustomFunctionData*)data)->swtch;
 }
 
-static bool gvar_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool gvar_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     gvar_t* gvar = (gvar_t*)(data + (bitoffs>>3UL));
     return *gvar != GVAR_MAX+1;
 }
 
-static bool fmd_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool fmd_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     uint32_t data_ofs = bitoffs >> 3UL;
     if (data_ofs == offsetof(ModelData, flightModeData)) {
@@ -612,3 +543,27 @@ static bool w_trainerMode(const YamlNode* node, uint32_t val,
 
   return true;
 }
+
+#if !defined(COLORLCD)
+static uint8_t select_tele_screen_data(void* user, uint8_t* data, uint32_t bitoffs)
+{
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(2);
+
+  auto md = reinterpret_cast<ModelData*>(data);
+  uint8_t st = (md->screensType >> (2 * idx)) & 0x03;
+  switch(st){
+  case TELEMETRY_SCREEN_TYPE_NONE:
+      break;
+  case TELEMETRY_SCREEN_TYPE_VALUES:
+      return 1; // lines
+  case TELEMETRY_SCREEN_TYPE_BARS:
+      return 0; // bars
+  case TELEMETRY_SCREEN_TYPE_SCRIPT:
+      return 2;
+  }
+
+  TRACE("select_tele_screen_data(idx=%d)", idx);
+  return 0;
+}
+#endif
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_t12.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_t12.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_t12.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_t12.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_t8.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_t8.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_t8.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_t8.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_tlite.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_tlite.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_tlite.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_tlite.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_tx12.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_tx12.cpp
index 658bf57bc..4e08a3b50 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_tx12.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_tx12.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_x7.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_x7.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_x7.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_x7.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_x9d.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_x9d.cpp
index 4ecd1fcfb..1897417c3 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_x9d.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_x9d.cpp
@@ -764,7 +764,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_x9e.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_x9e.cpp
index 506ce0e76..2ab5a5992 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_x9e.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_x9e.cpp
@@ -803,7 +803,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_x9lite.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_x9lite.cpp
index 8a2b98dad..2c0f9653c 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_x9lite.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_x9lite.cpp
@@ -736,7 +736,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_x9lites.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_x9lites.cpp
index 245a52698..76ba4a39c 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_x9lites.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_x9lites.cpp
@@ -746,7 +746,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_xlite.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_xlite.cpp
index 0d4de5fd3..e38e41470 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_xlite.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_xlite.cpp
@@ -743,7 +743,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_xlites.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_xlites.cpp
index aea0501cb..fc2e0a1fa 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_xlites.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_xlites.cpp
@@ -747,7 +747,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_funcs.cpp b/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
index 58ca54181..d136bfd25 100644
--- a/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
@@ -127,7 +127,7 @@ static bool w_vbat_max(const YamlNode* node, uint32_t val, yaml_writer_func wf,
 }
 
 #if defined(COLORLCD)
-static uint8_t select_zov(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_zov(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     data -= sizeof(ZoneOptionValueEnum);
@@ -138,7 +138,7 @@ static uint8_t select_zov(uint8_t* data, uint32_t bitoffs)
 }
 #endif
 
-static uint8_t select_mod_type(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_mod_type(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     data -= offsetof(ModuleData, ppm);
@@ -174,74 +174,86 @@ static uint8_t select_mod_type(uint8_t* data, uint32_t bitoffs)
     return 0;
 }
 
-static uint8_t select_custom_fn(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_custom_fn(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'all'
     //TODO
     return 1;
 }
 
-static uint8_t select_script_input(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_script_input(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'value'
     return 0;
 }
 
-static uint8_t select_id1(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_id1(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'id'
     return 0;
 }
 
-static uint8_t select_id2(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_id2(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'instance'
     return 0;
 }
 
-static uint8_t select_sensor_cfg(uint8_t* data, uint32_t bitoffs)
+static uint8_t select_sensor_cfg(void* user, uint8_t* data, uint32_t bitoffs)
 {
     // always use 'param'
     return 5;
 }
 
-static uint32_t sw_read(const char* val, uint8_t val_len)
+static uint32_t sw_read(void* user, const char* val, uint8_t val_len)
 {
-    uint32_t sw = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (sw >= MIXSRC_FIRST_SWITCH)
-        return sw - MIXSRC_FIRST_SWITCH;
+  (void)user;
+  uint32_t sw = yaml_parse_enum(enum_MixSources, val, val_len);
+  if (sw >= MIXSRC_FIRST_SWITCH) return sw - MIXSRC_FIRST_SWITCH;
 
-    return -1;
+  return -1;
 }
 
-static bool sw_write(uint32_t idx, yaml_writer_func wf, void* opaque)
+static bool sw_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_SWITCH, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
+
+  const char* str =
+      yaml_output_enum(idx + MIXSRC_FIRST_SWITCH, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-static void r_stick_name(const YamlNode* node, uint8_t* data,
-                         uint32_t bitoffs, uint16_t idx,
+static void r_stick_name(void* user, uint8_t* data, uint32_t bitoffs,
                          const char* val, uint8_t val_len)
 {
-    data -= offsetof(RadioData, switchConfig);
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+  if (idx >= NUM_STICKS) return;
+
+  data -= offsetof(RadioData, switchConfig);
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
 }
 
-static bool w_stick_name(const YamlNode* node, uint8_t* data,
-                         uint32_t bitoffs, uint16_t idx,
+static bool w_stick_name(void* user, uint8_t* data, uint32_t bitoffs,
                          yaml_writer_func wf, void* opaque)
 {
-    data -= offsetof(RadioData, switchConfig);
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    return wf(opaque, rd->anaNames[idx], strnlen(rd->anaNames[idx], LEN_ANA_NAME));
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+
+  data -= offsetof(RadioData, switchConfig);
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  return wf(opaque, rd->anaNames[idx],
+            strnlen(rd->anaNames[idx], LEN_ANA_NAME));
 }
 
-static bool stick_name_valid(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool stick_name_valid(void* user, uint8_t* data, uint32_t bitoffs)
 {
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    return rd->anaNames[idx][0] != '\0';
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  return rd->anaNames[idx][0] != '\0';
 }
 
 static const struct YamlNode struct_sticksConfig[] = {
@@ -250,27 +262,34 @@ static const struct YamlNode struct_sticksConfig[] = {
     YAML_END
 };
 
-static void sw_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                         uint16_t idx, const char* val, uint8_t val_len)
+static void sw_name_read(void* user, uint8_t* data, uint32_t bitoffs,
+                         const char* val, uint8_t val_len)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, switchConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    strncpy(rd->switchNames[idx], val, std::min<uint8_t>(val_len, LEN_SWITCH_NAME));
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, switchConfig);
+
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  strncpy(rd->switchNames[idx], val,
+          std::min<uint8_t>(val_len, LEN_SWITCH_NAME));
 }
 
-static bool sw_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, yaml_writer_func wf, void* opaque)
+static bool sw_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                          yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, switchConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    const char* str = rd->switchNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_SWITCH_NAME));
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, switchConfig);
+
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  const char* str = rd->switchNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_SWITCH_NAME));
 }
 
 static const struct YamlIdStr enum_SwitchConfig[] = {
@@ -282,50 +301,59 @@ static const struct YamlIdStr enum_SwitchConfig[] = {
 };
 
 static const struct YamlNode struct_switchConfig[] = {
-    YAML_IDX_CUST( "sw", sw_read, sw_write ),
+    YAML_IDX_CUST( "sw", sw_read, sw_write),
     YAML_ENUM( "type", 2, enum_SwitchConfig),
     YAML_CUSTOM( "name", sw_name_read, sw_name_write),
     YAML_END
 };
 
-static uint32_t pot_read(const char* val, uint8_t val_len)
+static uint32_t pot_read(void* user, const char* val, uint8_t val_len)
 {
-    uint32_t pot = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (pot >= MIXSRC_FIRST_POT)
-        return pot - MIXSRC_FIRST_POT;
+  (void)user;
+  uint32_t pot = yaml_parse_enum(enum_MixSources, val, val_len);
+  if (pot >= MIXSRC_FIRST_POT) return pot - MIXSRC_FIRST_POT;
 
-    return -1;
+  return -1;
 }
 
-static bool pot_write(uint32_t idx, yaml_writer_func wf, void* opaque)
+static bool pot_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_POT, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
+
+  const char* str = yaml_output_enum(idx + MIXSRC_FIRST_POT, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-static void pot_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, const char* val, uint8_t val_len)
+static void pot_name_read(void* user, uint8_t* data, uint32_t bitoffs,
+                          const char* val, uint8_t val_len)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, potsConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS;
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, potsConfig);
+
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS;
+  strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
 }
 
-static bool pot_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                           uint16_t idx, yaml_writer_func wf, void* opaque)
+static bool pot_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                           yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
-    data -= ((idx + 1) * 2) / 8;
-    data -= offsetof(RadioData, potsConfig);
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS;
-    const char* str = rd->anaNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
+  // data / bitoffs already incremented
+  data -= ((idx + 1) * 2) / 8;
+  data -= offsetof(RadioData, potsConfig);
+
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS;
+  const char* str = rd->anaNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
 }
 
 static const struct YamlIdStr enum_PotConfig[] = {
@@ -343,62 +371,72 @@ static const struct YamlNode struct_potConfig[] = {
     YAML_END
 };
 
-static uint32_t slider_read(const char* val, uint8_t val_len)
+static uint32_t slider_read(void* user, const char* val, uint8_t val_len)
 {
-    uint32_t sl = yaml_parse_enum(enum_MixSources, val, val_len);
-    if (sl >= MIXSRC_FIRST_SLIDER)
-        return sl - MIXSRC_FIRST_SLIDER;
+  (void)user;
+  uint32_t sl = yaml_parse_enum(enum_MixSources, val, val_len);
+  if (sl >= MIXSRC_FIRST_SLIDER) return sl - MIXSRC_FIRST_SLIDER;
 
-    return -1;
+  return -1;
 }
 
-static bool slider_write(uint32_t idx, yaml_writer_func wf, void* opaque)
+static bool slider_write(void* user, yaml_writer_func wf, void* opaque)
 {
-    const char* str = yaml_output_enum(idx + MIXSRC_FIRST_SLIDER, enum_MixSources);
-    return str ? wf(opaque, str, strlen(str)) : true;
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts();
+
+  const char* str =
+      yaml_output_enum(idx + MIXSRC_FIRST_SLIDER, enum_MixSources);
+  return str ? wf(opaque, str, strlen(str)) : true;
 }
 
-static void sl_name_read(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                         uint16_t idx, const char* val, uint8_t val_len)
+static void sl_name_read(void* user, uint8_t* data, uint32_t bitoffs,
+                         const char* val, uint8_t val_len)
 {
-    // data / bitoffs already incremented
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+
+  // data / bitoffs already incremented
 #if defined(PCBTARANIS)
-    // Please note:
-    //   slidersConfig is defined as a bit-field member,
-    //   so let's take the next field and subtract 1
-    //
-    data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
-    data -= offsetof(RadioData, potsConfig) - 1;
+  // Please note:
+  //   slidersConfig is defined as a bit-field member,
+  //   so let's take the next field and subtract 1
+  //
+  data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
+  data -= offsetof(RadioData, potsConfig) - 1;
 #else
-    data -= (idx + 1) / 8;
-    data -= offsetof(RadioData, slidersConfig);
+  data -= (idx + 1) / 8;
+  data -= offsetof(RadioData, slidersConfig);
 #endif
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS + STORAGE_NUM_POTS;
-    strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS + STORAGE_NUM_POTS;
+  strncpy(rd->anaNames[idx], val, std::min<uint8_t>(val_len, LEN_ANA_NAME));
 }
 
-static bool sl_name_write(const YamlNode* node, uint8_t* data, uint32_t bitoffs,
-                          uint16_t idx, yaml_writer_func wf, void* opaque)
+static bool sl_name_write(void* user, uint8_t* data, uint32_t bitoffs,
+                          yaml_writer_func wf, void* opaque)
 {
-    // data / bitoffs already incremented
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(1);
+
+  // data / bitoffs already incremented
 #if defined(PCBTARANIS)
-    // Please note:
-    //   slidersConfig is defined as a bit-field member,
-    //   so let's take the next field and subtract 1
-    //
-    data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
-    data -= offsetof(RadioData, potsConfig) - 1;
+  // Please note:
+  //   slidersConfig is defined as a bit-field member,
+  //   so let's take the next field and subtract 1
+  //
+  data -= (idx + 4 /* bitsize previous field (auxSerialMode) */ + 1) / 8;
+  data -= offsetof(RadioData, potsConfig) - 1;
 #else
-    data -= (idx + 1) / 8;
-    data -= offsetof(RadioData, slidersConfig);
+  data -= (idx + 1) / 8;
+  data -= offsetof(RadioData, slidersConfig);
 #endif
 
-    RadioData* rd = reinterpret_cast<RadioData*>(data);
-    idx += NUM_STICKS + STORAGE_NUM_POTS;
-    const char* str = rd->anaNames[idx];
-    return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
+  RadioData* rd = reinterpret_cast<RadioData*>(data);
+  idx += NUM_STICKS + STORAGE_NUM_POTS;
+  const char* str = rd->anaNames[idx];
+  return wf(opaque, str, strnlen(str, LEN_ANA_NAME));
 }
 
 static const struct YamlIdStr enum_SliderConfig[] = {
@@ -514,19 +552,19 @@ static bool w_swtchSrc(const YamlNode* node, uint32_t val, yaml_writer_func wf,
     return wf(opaque, str, strlen(str));
 }
 
-static bool cfn_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool cfn_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     data += bitoffs >> 3UL;
     return ((CustomFunctionData*)data)->swtch;
 }
 
-static bool gvar_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool gvar_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     gvar_t* gvar = (gvar_t*)(data + (bitoffs>>3UL));
     return *gvar != GVAR_MAX+1;
 }
 
-static bool fmd_is_active(uint8_t* data, uint32_t bitoffs, uint16_t idx)
+static bool fmd_is_active(void* user, uint8_t* data, uint32_t bitoffs)
 {
     uint32_t data_ofs = bitoffs >> 3UL;
     if (data_ofs == offsetof(ModelData, flightModeData)) {
@@ -727,3 +765,27 @@ static bool w_trainerMode(const YamlNode* node, uint32_t val,
 
   return true;
 }
+
+#if !defined(COLORLCD)
+static uint8_t select_tele_screen_data(void* user, uint8_t* data, uint32_t bitoffs)
+{
+  auto tw = reinterpret_cast<YamlTreeWalker*>(user);
+  uint16_t idx = tw->getElmts(2);
+
+  auto md = reinterpret_cast<ModelData*>(data);
+  uint8_t st = (md->screensType >> (2 * idx)) & 0x03;
+  switch(st){
+  case TELEMETRY_SCREEN_TYPE_NONE:
+      break;
+  case TELEMETRY_SCREEN_TYPE_VALUES:
+      return 1; // lines
+  case TELEMETRY_SCREEN_TYPE_BARS:
+      return 0; // bars
+  case TELEMETRY_SCREEN_TYPE_SCRIPT:
+      return 2;
+  }
+
+  TRACE("select_tele_screen_data(idx=%d)", idx);
+  return 0;
+}
+#endif
diff --git a/radio/src/storage/yaml/yaml_datastructs_t12.cpp b/radio/src/storage/yaml/yaml_datastructs_t12.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/yaml/yaml_datastructs_t12.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_t12.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_t8.cpp b/radio/src/storage/yaml/yaml_datastructs_t8.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/yaml/yaml_datastructs_t8.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_t8.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_tlite.cpp b/radio/src/storage/yaml/yaml_datastructs_tlite.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/yaml/yaml_datastructs_tlite.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_tlite.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_tx12.cpp b/radio/src/storage/yaml/yaml_datastructs_tx12.cpp
index 658bf57bc..4e08a3b50 100644
--- a/radio/src/storage/yaml/yaml_datastructs_tx12.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_tx12.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_x7.cpp b/radio/src/storage/yaml/yaml_datastructs_x7.cpp
index 433343d0f..3a4d01222 100644
--- a/radio/src/storage/yaml/yaml_datastructs_x7.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_x7.cpp
@@ -751,7 +751,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_x9d.cpp b/radio/src/storage/yaml/yaml_datastructs_x9d.cpp
index 4ecd1fcfb..1897417c3 100644
--- a/radio/src/storage/yaml/yaml_datastructs_x9d.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_x9d.cpp
@@ -764,7 +764,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_x9e.cpp b/radio/src/storage/yaml/yaml_datastructs_x9e.cpp
index 506ce0e76..2ab5a5992 100644
--- a/radio/src/storage/yaml/yaml_datastructs_x9e.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_x9e.cpp
@@ -803,7 +803,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_x9lite.cpp b/radio/src/storage/yaml/yaml_datastructs_x9lite.cpp
index 8a2b98dad..2c0f9653c 100644
--- a/radio/src/storage/yaml/yaml_datastructs_x9lite.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_x9lite.cpp
@@ -736,7 +736,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_x9lites.cpp b/radio/src/storage/yaml/yaml_datastructs_x9lites.cpp
index 245a52698..76ba4a39c 100644
--- a/radio/src/storage/yaml/yaml_datastructs_x9lites.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_x9lites.cpp
@@ -746,7 +746,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_xlite.cpp b/radio/src/storage/yaml/yaml_datastructs_xlite.cpp
index 0d4de5fd3..e38e41470 100644
--- a/radio/src/storage/yaml/yaml_datastructs_xlite.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_xlite.cpp
@@ -743,7 +743,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_datastructs_xlites.cpp b/radio/src/storage/yaml/yaml_datastructs_xlites.cpp
index aea0501cb..fc2e0a1fa 100644
--- a/radio/src/storage/yaml/yaml_datastructs_xlites.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_xlites.cpp
@@ -747,7 +747,7 @@ static const struct YamlNode union_TelemetryScreenData_elmts[] = {
 };
 static const struct YamlNode union_TelemetryScreenData[] = {
   YAML_IDX,
-  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, NULL),
+  YAML_UNION("u", 192, union_TelemetryScreenData_elmts, select_tele_screen_data),
   YAML_END
 };
 static const struct YamlNode struct_ModelData[] = {
diff --git a/radio/src/storage/yaml/yaml_node.h b/radio/src/storage/yaml/yaml_node.h
index 42a515b0a..1eed24cb1 100644
--- a/radio/src/storage/yaml/yaml_node.h
+++ b/radio/src/storage/yaml/yaml_node.h
@@ -53,59 +53,62 @@ typedef bool (*yaml_writer_func)(void* opaque, const char* str, size_t len);
 
 struct YamlNode
 {
-    typedef bool (*is_active_func)(uint8_t* data, uint32_t bitoffs, uint16_t idx);
+  typedef bool (*is_active_func)(void* user, uint8_t* data, uint32_t bitoffs);
 
-    typedef uint32_t (*cust_to_uint_func)(const YamlNode* node, const char* val, uint8_t val_len);
+  typedef uint32_t (*cust_to_uint_func)(const YamlNode* node, const char* val,
+                                        uint8_t val_len);
 
-    typedef bool (*uint_to_cust_func)(const YamlNode* node, uint32_t val, yaml_writer_func wf, void* opaque);
-
-    typedef uint8_t (*select_member_func)(uint8_t* data, uint32_t bitoffs);
-
-    typedef uint32_t (*cust_idx_read_func)(const char* val, uint8_t val_len);
-    typedef bool (*cust_idx_write_func)(uint32_t idx, yaml_writer_func wf, void* opaque);
-
-    typedef void (*cust_read_func)(const YamlNode* node, uint8_t* data,
-                                   uint32_t bitoffs, uint16_t idx,
-                                   const char* val, uint8_t val_len);
-    typedef bool (*cust_write_func)(const YamlNode* node, uint8_t* data,
-                                    uint32_t bitoffs, uint16_t idx,
+  typedef bool (*uint_to_cust_func)(const YamlNode* node, uint32_t val,
                                     yaml_writer_func wf, void* opaque);
 
-    uint8_t      type;
-    uint32_t     size;  // bits
-    uint8_t      tag_len;
-    const char*  tag;
-    union {
-        struct {
-            const YamlNode* child;
-            union {
-                struct {
-                    is_active_func  is_active;
-                    uint16_t        elmts; // maximum number of elements
-                } _a;
-                select_member_func select_member;
-            } u;
-        } _array;
+  typedef uint8_t (*select_member_func)(void* user, uint8_t* data,
+                                        uint32_t bitoffs);
 
-        struct {
-            const YamlIdStr* choices;
-        } _enum;
+  typedef uint32_t (*cust_idx_read_func)(void* user, const char* val,
+                                         uint8_t val_len);
+  typedef bool (*cust_idx_write_func)(void* user, yaml_writer_func wf,
+                                      void* opaque);
 
-        struct {
-            cust_to_uint_func cust_to_uint;
-            uint_to_cust_func uint_to_cust;
-        } _cust;
+  typedef void (*cust_read_func)(void* user, uint8_t* data, uint32_t bitoffs,
+                                 const char* val, uint8_t val_len);
+  typedef bool (*cust_write_func)(void* user, uint8_t* data, uint32_t bitoffs,
+                                  yaml_writer_func wf, void* opaque);
 
+  uint8_t type;
+  uint32_t size;  // bits
+  uint8_t tag_len;
+  const char* tag;
+  union {
+    struct {
+      const YamlNode* child;
+      union {
         struct {
-            cust_idx_read_func  read;
-            cust_idx_write_func write;
-        } _cust_idx;
+          is_active_func is_active;
+          uint16_t elmts;  // maximum number of elements
+        } _a;
+        select_member_func select_member;
+      } u;
+    } _array;
 
-        struct {
-            cust_read_func  read;
-            cust_write_func write;
-        } _cust_attr;
-    } u;
+    struct {
+      const YamlIdStr* choices;
+    } _enum;
+
+    struct {
+      cust_to_uint_func cust_to_uint;
+      uint_to_cust_func uint_to_cust;
+    } _cust;
+
+    struct {
+      cust_idx_read_func read;
+      cust_idx_write_func write;
+    } _cust_idx;
+
+    struct {
+      cust_read_func read;
+      cust_write_func write;
+    } _cust_attr;
+  } u;
 };
 
 #if !defined(_MSC_VER)
diff --git a/radio/src/storage/yaml/yaml_tree_walker.cpp b/radio/src/storage/yaml/yaml_tree_walker.cpp
index f9f2914dd..792c13ccb 100644
--- a/radio/src/storage/yaml/yaml_tree_walker.cpp
+++ b/radio/src/storage/yaml/yaml_tree_walker.cpp
@@ -49,24 +49,25 @@ uint32_t yaml_parse_enum(const struct YamlIdStr* choices, const char* val, uint8
     return choices->id;
 }
 
-static void yaml_set_attr(uint8_t* ptr, uint32_t bit_ofs, const YamlNode* node,
-                          uint16_t idx, const char* val, uint8_t val_len)
+static void yaml_set_attr(void* user, uint8_t* ptr, uint32_t bit_ofs,
+                          const YamlNode* node, const char* val,
+                          uint8_t val_len)
 {
-    uint32_t i = 0;
+  uint32_t i = 0;
 
-    //TRACE("set(%s, %.*s, bit-ofs=%u, bits=%u)\n",
-    //       node->tag, val_len, val, bit_ofs, node->size);
+  // TRACE("set(%s, %.*s, bit-ofs=%u, bits=%u)\n",
+  //       node->tag, val_len, val, bit_ofs, node->size);
 
-    ptr += bit_ofs >> 3UL;
-    bit_ofs &= 0x07;
+  ptr += bit_ofs >> 3UL;
+  bit_ofs &= 0x07;
 
-    if (node->type == YDT_STRING) {
-        //assert(!bit_ofs);
-        copy_string((char*)ptr, val, MIN(val_len, node->size - 1));
-        return;
-    }
+  if (node->type == YDT_STRING) {
+    // assert(!bit_ofs);
+    copy_string((char*)ptr, val, MIN(val_len, node->size - 1));
+    return;
+  }
 
-    switch(node->type) {
+  switch (node->type) {
     case YDT_SIGNED:
         i = node->u._cust.cust_to_uint ? node->u._cust.cust_to_uint(node, val, val_len)
             : (uint32_t)yaml_str2int(val, val_len);
@@ -80,7 +81,7 @@ static void yaml_set_attr(uint8_t* ptr, uint32_t bit_ofs, const YamlNode* node,
         break;
     case YDT_CUSTOM:
         if (node->u._cust_attr.read)
-            node->u._cust_attr.read(node, ptr, bit_ofs, idx, val, val_len);
+            node->u._cust_attr.read(user, ptr, bit_ofs, val, val_len);
         return;
     default:
         break;
@@ -130,71 +131,64 @@ static bool yaml_output_string(const char* str, uint32_t max_len,
     return true;
 }
 
-static bool yaml_output_attr(uint8_t* ptr, uint32_t bit_ofs, const YamlNode* node,
-                             uint16_t idx, yaml_writer_func wf, void* opaque)
+static bool yaml_output_attr(void* user, uint8_t* ptr, uint32_t bit_ofs,
+                             const YamlNode* node, yaml_writer_func wf,
+                             void* opaque)
 {
-    if (node->type == YDT_NONE)
+  if (node->type == YDT_NONE) return false;
+
+  if (node->type == YDT_PADDING) return true;
+
+  // output tag
+  if (!wf(opaque, node->tag, node->tag_len)) return false;
+
+  if (!wf(opaque, ": ", 2)) return false;
+
+  if (ptr) {
+    ptr += bit_ofs >> 3UL;
+    bit_ofs &= 0x07;
+
+    const char* p_out = NULL;
+    if (node->type == YDT_STRING) {
+      // assert(!bit_ofs);
+      if (!yaml_output_string((const char*)ptr, (node->size) >> 3UL, wf,
+                              opaque))
         return false;
-    
-    if (node->type == YDT_PADDING)
-        return true;
-    
-    // output tag
-    if (!wf(opaque, node->tag, node->tag_len))
+    } else if (node->type == YDT_CUSTOM) {
+      if (node->u._cust_attr.write &&
+          !node->u._cust_attr.write(user, ptr, bit_ofs, wf, opaque))
         return false;
+    } else {
+      unsigned int i = yaml_get_bits(ptr, bit_ofs, node->size);
 
-    if (!wf(opaque, ": ", 2))
-        return false;
+      if ((node->type == YDT_SIGNED || node->type == YDT_UNSIGNED) &&
+          node->u._cust.uint_to_cust) {
+        return node->u._cust.uint_to_cust(node, i, wf, opaque) &&
+               wf(opaque, "\r\n", 2);
+      } else {
+        switch (node->type) {
+          case YDT_SIGNED:
+            p_out = yaml_signed2str((int)yaml_to_signed(i, node->size));
+            break;
+          case YDT_UNSIGNED:
+            p_out = yaml_unsigned2str(i);
+            break;
+          case YDT_ENUM:
+            p_out = yaml_output_enum(i, node->u._enum.choices);
+            break;
 
-    if (ptr) {
-    
-        ptr += bit_ofs >> 3UL;
-        bit_ofs &= 0x07;
-
-        const char* p_out = NULL;
-        if (node->type == YDT_STRING) {
-            //assert(!bit_ofs);
-            if (!yaml_output_string((const char*)ptr, (node->size)>>3UL, wf, opaque))
-                return false;
+          case YDT_ARRAY:
+          case YDT_UNION:
+          default:
+            break;
         }
-        else if (node->type == YDT_CUSTOM) {
-            if (node->u._cust_attr.write
-                && !node->u._cust_attr.write(node, ptr, bit_ofs, idx, wf, opaque))
-                return false;
-        }
-        else {
-            unsigned int i = yaml_get_bits(ptr, bit_ofs, node->size);
-
-            if ((node->type == YDT_SIGNED || node->type == YDT_UNSIGNED)
-                && node->u._cust.uint_to_cust) {
-                return node->u._cust.uint_to_cust(node, i, wf, opaque)
-                    && wf(opaque, "\r\n", 2);
-            }
-            else {
-                switch(node->type) {
-                case YDT_SIGNED:
-                    p_out = yaml_signed2str((int)yaml_to_signed(i, node->size));
-                    break;
-                case YDT_UNSIGNED:
-                    p_out = yaml_unsigned2str(i);
-                    break;
-                case YDT_ENUM:
-                    p_out = yaml_output_enum(i, node->u._enum.choices);
-                    break;
-
-                case YDT_ARRAY:
-                case YDT_UNION:
-                default:
-                    break;
-                }
-            }
-        }
-
-        if (p_out && !wf(opaque, p_out, strlen(p_out)))
-            return false;
+      }
     }
 
-    return wf(opaque, "\r\n", 2);
+    if (p_out && !wf(opaque, p_out, strlen(p_out))) return false;
+  }
+
+  return wf(opaque, "\r\n", 2);
 }
 
 YamlTreeWalker::YamlTreeWalker()
@@ -389,7 +383,7 @@ bool YamlTreeWalker::isElmtEmpty(uint8_t* data)
 
         // assume structs aligned on 8bit boundaries
         if (node->u._array.u._a.is_active)
-            return !node->u._array.u._a.is_active(data, bit_ofs, getElmts());
+            return !node->u._array.u._a.is_active(this, data, bit_ofs);
 
         return yaml_is_zero(data, bit_ofs, node->size);
     }
@@ -452,7 +446,7 @@ void YamlTreeWalker::setAttrValue(char* buf, uint8_t len)
 
         uint32_t i = 0;
         if (attr->u._cust_idx.read)
-            i = attr->u._cust_idx.read(buf, len);
+            i = attr->u._cust_idx.read(this, buf, len);
         else
             i = yaml_str2uint(buf, len);
 
@@ -465,7 +459,7 @@ void YamlTreeWalker::setAttrValue(char* buf, uint8_t len)
         }
     }
     else {
-        yaml_set_attr(data, getBitOffset(), attr, getParentElmts(), buf, len);
+        yaml_set_attr(this, data, getBitOffset(), attr, buf, len);
     }
 }
 
@@ -533,19 +527,20 @@ bool YamlTreeWalker::generate(yaml_writer_func wf, void* opaque)
                 for(int i=2; i < getLevel(); i++)
                     if (!wf(opaque, "   ", 3))
                         return false;
-                if (!yaml_output_attr(NULL, 0, node, 0, wf, opaque))
+                if (!yaml_output_attr(this, NULL, 0, node, wf, opaque))
                     return false; // TODO: error handling???
 
                 // grab attr idx...
-                uint8_t idx = node->u._array.u.select_member(data, getBitOffset());
-                //TRACE("<idx = %d>", idx);
+                uint8_t idx =
+                    node->u._array.u.select_member(this, data, getBitOffset());
+                // TRACE("<idx = %d>", idx);
                 setAttrIdx(idx);
 
                 attr = getAttr();
                 for(int i=1; i < getLevel(); i++)
                     if (!wf(opaque, "   ", 3))
                         return false;
-                if (!yaml_output_attr(data, getBitOffset(), attr, 0, wf, opaque))
+                if (!yaml_output_attr(this, data, getBitOffset(), attr, wf, opaque))
                     return false; // TODO: error handling???
 
                 if (attr->type != YDT_ARRAY
@@ -578,7 +573,7 @@ bool YamlTreeWalker::generate(yaml_writer_func wf, void* opaque)
                 for(int i=2; i < getLevel(); i++)
                     if (!wf(opaque, "   ", 3))
                         return false;
-                if (!yaml_output_attr(NULL, 0, getNode(),0, wf, opaque))
+                if (!yaml_output_attr(this, NULL, 0, getNode(), wf, opaque))
                     return false; // TODO: error handling???
                 continue;
             }
@@ -600,7 +595,7 @@ bool YamlTreeWalker::generate(yaml_writer_func wf, void* opaque)
                     return false;
 
             if (attr->u._cust_idx.write) {
-                if (!attr->u._cust_idx.write(getElmts(),wf,opaque))
+                if (!attr->u._cust_idx.write(this,wf,opaque))
                     return false;
             }
             else {
@@ -633,7 +628,7 @@ bool YamlTreeWalker::generate(yaml_writer_func wf, void* opaque)
                 if (!wf(opaque, "   ", 3))
                     return false;
             
-            if (!yaml_output_attr(data, getBitOffset(), attr, getParentElmts(), wf, opaque))
+            if (!yaml_output_attr(this, data, getBitOffset(), attr, wf, opaque))
                 return false; // TODO: error handling???
         }
 
diff --git a/radio/src/storage/yaml/yaml_tree_walker.h b/radio/src/storage/yaml/yaml_tree_walker.h
index c27da5c91..913f77350 100644
--- a/radio/src/storage/yaml/yaml_tree_walker.h
+++ b/radio/src/storage/yaml/yaml_tree_walker.h
@@ -132,14 +132,12 @@ public:
         return NULL;
     }
 
-    uint16_t getElmts() {
-        return stack[stack_level].elmts;
+    uint16_t getElmts(uint8_t lvl = 0) {
+        if (stack_level + lvl >= NODE_STACK_DEPTH)
+            return 0;
+        return stack[stack_level + lvl].elmts;
     }
 
-    uint16_t getParentElmts() {
-        return empty() ? 0 : stack[stack_level + 1].elmts;
-    }
-    
     // Increment the cursor until a match is found or the end of
     // the current collection (node of type YDT_NONE) is reached.
     //