diff --git a/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp b/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
index e91a1970d..fcb2f31f7 100644
--- a/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
+++ b/radio/src/storage/conversions/yaml/yaml_datastructs_funcs.cpp
@@ -748,7 +748,7 @@ bool w_customFn(void* user, uint8_t* data, uint32_t bitoffs,
     str = yaml_unsigned2str(CFN_CH_INDEX(cfn)); // CH index
     if (!wf(opaque, str, strlen(str))) return false;
     if (!wf(opaque, ",", 1)) return false;
-    str = yaml_unsigned2str(CFN_PARAM(cfn));    // value
+    str = yaml_signed2str(CFN_PARAM(cfn));    // value
     if (!wf(opaque, str, strlen(str))) return false;
     break;
 
diff --git a/radio/src/storage/yaml/yaml_datastructs_funcs.cpp b/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
index 8fcbce1a3..8cb3925c4 100644
--- a/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
+++ b/radio/src/storage/yaml/yaml_datastructs_funcs.cpp
@@ -1051,6 +1051,7 @@ static void r_customFn(void* user, uint8_t* data, uint32_t bitoffs,
     CFN_CH_INDEX(cfn) = yaml_str2uint_ref(val, val_len);
     // ","
     if (!val_len || val[0] != ',') return;
+    val++; val_len--;
     // value
     CFN_PARAM(cfn) = yaml_str2int_ref(val, val_len);
   }
@@ -1235,7 +1236,7 @@ static bool w_customFn(void* user, uint8_t* data, uint32_t bitoffs,
     str = yaml_unsigned2str(CFN_CH_INDEX(cfn)); // CH index
     if (!wf(opaque, str, strlen(str))) return false;
     if (!wf(opaque, ",", 1)) return false;
-    str = yaml_unsigned2str(CFN_PARAM(cfn));    // value
+    str = yaml_signed2str(CFN_PARAM(cfn));    // value
     if (!wf(opaque, str, strlen(str))) return false;
     break;
 
diff --git a/radio/src/tests/conversions.cpp b/radio/src/tests/conversions.cpp
index 5167f78f4..8bae7eb6f 100644
--- a/radio/src/tests/conversions.cpp
+++ b/radio/src/tests/conversions.cpp
@@ -442,6 +442,10 @@ TEST(Conversions, ConversionTX16SFrom25)
   EXPECT_EQ(MODULE_SUBTYPE_PXX1_ACCST_LR12, g_model.moduleData[1].subType);
   EXPECT_EQ(4, g_model.moduleData[1].channelsCount); // 4 + 8 = 12
 
+  EXPECT_EQ(-SWSRC_SE0, g_model.customFn[0].swtch);
+  EXPECT_EQ(FUNC_OVERRIDE_CHANNEL, g_model.customFn[0].func);
+  EXPECT_EQ(-100, CFN_PARAM(&(g_model.customFn[0])));
+  
   const auto& top_widget = g_model.topbarData.zones[3];
   EXPECT_STRNEQ("Value", top_widget.widgetName);
 
diff --git a/radio/src/tests/model_25_tx16s.otx b/radio/src/tests/model_25_tx16s.otx
index 2555135b2..d9a764880 100644
Binary files a/radio/src/tests/model_25_tx16s.otx and b/radio/src/tests/model_25_tx16s.otx differ