diff --git a/radio/src/Makefile b/radio/src/Makefile
index 8237687e9..79b768a07 100644
--- a/radio/src/Makefile
+++ b/radio/src/Makefile
@@ -781,7 +781,7 @@ ifeq ($(PCB), TARANIS)
     endif
     CPPDEFS += -DLUA
     INCDIRS += lua/src
-    CPPSRC += lua.cpp
+    CPPSRC += lua_api.cpp
     LUASRC = lua/src/lapi.c lua/src/lcode.c lua/src/lctype.c lua/src/ldebug.c lua/src/ldo.c lua/src/ldump.c lua/src/lfunc.c lua/src/lgc.c lua/src/llex.c lua/src/lmem.c \
            lua/src/lobject.c lua/src/lopcodes.c lua/src/lparser.c lua/src/lstate.c lua/src/lstring.c lua/src/ltable.c lua/src/lrotable.c lua/src/ltm.c lua/src/lundump.c lua/src/lvm.c lua/src/lzio.c \
            lua/src/lbaselib.c lua/src/linit.c lua/src/lmathlib.c lua/src/lbitlib.c lua/src/loadlib.c lua/src/lauxlib.c lua/src/ltablib.c lua/src/lcorolib.c
diff --git a/radio/src/lua.cpp b/radio/src/lua_api.cpp
similarity index 90%
rename from radio/src/lua.cpp
rename to radio/src/lua_api.cpp
index 8890e6392..3a267e03a 100644
--- a/radio/src/lua.cpp
+++ b/radio/src/lua_api.cpp
@@ -72,6 +72,7 @@ ScriptInputsOutputs scriptInputsOutputs[MAX_SCRIPTS] = { {0} };
 ScriptInternalData standaloneScript = { SCRIPT_NOFILE, 0 };
 uint16_t maxLuaInterval = 0;
 uint16_t maxLuaDuration = 0;
+bool luaLcdAllowed;
 
 #define PERMANENT_SCRIPTS_MAX_INSTRUCTIONS (10000/100)
 #define MANUAL_SCRIPTS_MAX_INSTRUCTIONS    (20000/100)
@@ -341,14 +342,20 @@ static int luaGetGeneralSettings(lua_State *L)
   return 1;
 }
 
+static int luaLcdLock(lua_State *L)
+{
+  return 0;
+}
+
 static int luaLcdClear(lua_State *L)
 {
-  lcd_clear();
+  if (luaLcdAllowed) lcd_clear();
   return 0;
 }
 
 static int luaLcdDrawPoint(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   lcd_plot(x, y);
@@ -357,6 +364,7 @@ static int luaLcdDrawPoint(lua_State *L)
 
 static int luaLcdDrawLine(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x1 = luaL_checkinteger(L, 1);
   int y1 = luaL_checkinteger(L, 2);
   int x2 = luaL_checkinteger(L, 3);
@@ -375,6 +383,7 @@ static int luaLcdGetLastPos(lua_State *L)
 
 static int luaLcdDrawText(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   const char * s = luaL_checkstring(L, 3);
@@ -385,6 +394,7 @@ static int luaLcdDrawText(lua_State *L)
 
 static int luaLcdDrawTimer(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int seconds = luaL_checkinteger(L, 3);
@@ -395,6 +405,7 @@ static int luaLcdDrawTimer(lua_State *L)
 
 static int luaLcdDrawNumber(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int n = luaL_checkinteger(L, 3);
@@ -405,6 +416,7 @@ static int luaLcdDrawNumber(lua_State *L)
 
 static int luaLcdDrawChannel(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int channel = -1;
@@ -427,6 +439,7 @@ static int luaLcdDrawChannel(lua_State *L)
 
 static int luaLcdDrawSwitch(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int s = luaL_checkinteger(L, 3);
@@ -437,6 +450,7 @@ static int luaLcdDrawSwitch(lua_State *L)
 
 static int luaLcdDrawSource(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int s = luaL_checkinteger(L, 3);
@@ -447,6 +461,7 @@ static int luaLcdDrawSource(lua_State *L)
 
 static int luaLcdDrawPixmap(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   const char * filename = luaL_checkstring(L, 3);
@@ -460,6 +475,7 @@ static int luaLcdDrawPixmap(lua_State *L)
 
 static int luaLcdDrawRectangle(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int w = luaL_checkinteger(L, 3);
@@ -470,6 +486,7 @@ static int luaLcdDrawRectangle(lua_State *L)
 
 static int luaLcdDrawFilledRectangle(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int w = luaL_checkinteger(L, 3);
@@ -481,6 +498,7 @@ static int luaLcdDrawFilledRectangle(lua_State *L)
 
 static int luaLcdDrawGauge(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int w = luaL_checkinteger(L, 3);
@@ -498,6 +516,7 @@ static int luaLcdDrawGauge(lua_State *L)
 
 static int luaLcdDrawScreenTitle(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   const char * str = luaL_checkstring(L, 1);
   int idx = luaL_checkinteger(L, 2);
   int cnt = luaL_checkinteger(L, 3);
@@ -511,6 +530,7 @@ static int luaLcdDrawScreenTitle(lua_State *L)
 
 static int luaLcdDrawCombobox(lua_State *L)
 {
+  if (! luaLcdAllowed) return 0;
   int x = luaL_checkinteger(L, 1);
   int y = luaL_checkinteger(L, 2);
   int w = luaL_checkinteger(L, 3);
@@ -1411,6 +1431,7 @@ const luaL_Reg modelLib[] = {
 };
 
 const luaL_Reg lcdLib[] = {
+  { "lock", luaLcdLock },
   { "clear", luaLcdClear },
   { "getLastPos", luaLcdGetLastPos },
   { "drawPoint", luaLcdDrawPoint },
@@ -1810,96 +1831,99 @@ void luaDoOneRunStandalone(uint8_t evt)
   }
 }
   
-void luaDoOneRunPermanentScript(uint8_t evt, int i)
+bool luaDoOneRunPermanentScript(uint8_t evt, int i, bool runGuiScripts)
 {
   ScriptInternalData & sid = scriptInternalData[i];
-  if (sid.state == SCRIPT_OK) {
-    SET_LUA_INSTRUCTIONS_COUNT(PERMANENT_SCRIPTS_MAX_INSTRUCTIONS);
-    int inputsCount = 0;
+  if (sid.state != SCRIPT_OK) return false;
+
+  SET_LUA_INSTRUCTIONS_COUNT(PERMANENT_SCRIPTS_MAX_INSTRUCTIONS);
+  int inputsCount = 0;
 #if defined(SIMU) || defined(DEBUG)
-    const char *filename;
+  const char *filename;
 #endif
-    ScriptInputsOutputs * sio = NULL;
+  ScriptInputsOutputs * sio = NULL;
 #if SCRIPT_MIX_FIRST > 0
-    if (sid.reference >= SCRIPT_MIX_FIRST && sid.reference <= SCRIPT_MIX_LAST) {
+  if (sid.reference >= SCRIPT_MIX_FIRST && sid.reference <= SCRIPT_MIX_LAST) {
 #else
-    if (sid.reference <= SCRIPT_MIX_LAST) {
+  if (sid.reference <= SCRIPT_MIX_LAST) {
 #endif
-      ScriptData & sd = g_model.scriptsData[sid.reference-SCRIPT_MIX_FIRST];
-      sio = &scriptInputsOutputs[sid.reference-SCRIPT_MIX_FIRST];
-      inputsCount = sio->inputsCount;
+    if (runGuiScripts) return false;    //mixer script is not gui script
+    ScriptData & sd = g_model.scriptsData[sid.reference-SCRIPT_MIX_FIRST];
+    sio = &scriptInputsOutputs[sid.reference-SCRIPT_MIX_FIRST];
+    inputsCount = sio->inputsCount;
 #if defined(SIMU) || defined(DEBUG)
-      filename = sd.file;
+    filename = sd.file;
 #endif
-      lua_rawgeti(L, LUA_REGISTRYINDEX, sid.run);
-      for (int j=0; j<sio->inputsCount; j++) {
-        if (sio->inputs[j].type == 1)
-          luaGetValueAndPush((uint8_t)sd.inputs[j]);
-        else
-          lua_pushinteger(L, sd.inputs[j] + sio->inputs[j].def);
-      }
+    lua_rawgeti(L, LUA_REGISTRYINDEX, sid.run);
+    for (int j=0; j<sio->inputsCount; j++) {
+      if (sio->inputs[j].type == 1)
+        luaGetValueAndPush((uint8_t)sd.inputs[j]);
+      else
+        lua_pushinteger(L, sd.inputs[j] + sio->inputs[j].def);
     }
-    else if (sid.reference >= SCRIPT_FUNC_FIRST && sid.reference <= SCRIPT_FUNC_LAST) {
-      CustomFunctionData & fn = g_model.customFn[sid.reference-SCRIPT_FUNC_FIRST];
-      if (!getSwitch(fn.swtch)) {
-        return;
-      }
+  }
+  else if (sid.reference >= SCRIPT_FUNC_FIRST && sid.reference <= SCRIPT_FUNC_LAST) {
+    CustomFunctionData & fn = g_model.customFn[sid.reference-SCRIPT_FUNC_FIRST];
+    if (runGuiScripts) return false;    //function script is not gui script
+    if (!getSwitch(fn.swtch)) return false;
 #if defined(SIMU) || defined(DEBUG)
-      filename = fn.play.name;
+    filename = fn.play.name;
 #endif
+    lua_rawgeti(L, LUA_REGISTRYINDEX, sid.run);
+  }
+  else {
+#if defined(SIMU) || defined(DEBUG)
+    TelemetryScriptData & script = g_model.frsky.screens[sid.reference-SCRIPT_TELEMETRY_FIRST].script;
+    filename = script.file;
+#endif
+    if (g_menuStack[0]==menuTelemetryFrsky && sid.reference==SCRIPT_TELEMETRY_FIRST+s_frsky_view) {
+      if (!runGuiScripts) return false;    //telemetry script gui part, do not run this time
       lua_rawgeti(L, LUA_REGISTRYINDEX, sid.run);
+      lua_pushinteger(L, evt);
+      inputsCount = 1;
+    }
+    else if (sid.background) {
+      if (runGuiScripts) return false;    //telemetry script non-gui part, do not run this time
+      lua_rawgeti(L, LUA_REGISTRYINDEX, sid.background);
     }
     else {
-#if defined(SIMU) || defined(DEBUG)
-      TelemetryScriptData & script = g_model.frsky.screens[sid.reference-SCRIPT_TELEMETRY_FIRST].script;
-      filename = script.file;
-#endif
-      if (g_menuStack[0]==menuTelemetryFrsky && sid.reference==SCRIPT_TELEMETRY_FIRST+s_frsky_view) {
-        lua_rawgeti(L, LUA_REGISTRYINDEX, sid.run);
-        lua_pushinteger(L, evt);
-        inputsCount = 1;
-      }
-      else if (sid.background) {
-        lua_rawgeti(L, LUA_REGISTRYINDEX, sid.background);
-      }
-      else {
-        return;
-      }
+      return false;
     }
+  }
 
-    if (lua_pcall(L, inputsCount, sio ? sio->outputsCount : 0, 0) == 0) {
-      if (sio) {
-        for (int j=sio->outputsCount-1; j>=0; j--) {
-          if (!lua_isnumber(L, -1)) {
-            sid.state = (instructionsPercent > 100 ? SCRIPT_KILLED : SCRIPT_SYNTAX_ERROR);
-            TRACE("Script %8s disabled", filename);
-            break;
-          }
-          sio->outputs[j].value = lua_tointeger(L, -1);
-          lua_pop(L, 1);
+  if (lua_pcall(L, inputsCount, sio ? sio->outputsCount : 0, 0) == 0) {
+    if (sio) {
+      for (int j=sio->outputsCount-1; j>=0; j--) {
+        if (!lua_isnumber(L, -1)) {
+          sid.state = (instructionsPercent > 100 ? SCRIPT_KILLED : SCRIPT_SYNTAX_ERROR);
+          TRACE("Script %8s disabled", filename);
+          break;
         }
-      }
-    }
-    else {
-      if (instructionsPercent > 100) {
-        TRACE("Script %8s killed", filename);
-        sid.state = SCRIPT_KILLED;
-      }
-      else {
-        TRACE("Script %8s error: %s", filename, lua_tostring(L, -1));
-        sid.state = SCRIPT_SYNTAX_ERROR;
-      }
-    }
-
-    if (sid.state != SCRIPT_OK) {
-      luaFree(sid);
-    }
-    else {
-      if (instructionsPercent > sid.instructions) {
-        sid.instructions = instructionsPercent;
+        sio->outputs[j].value = lua_tointeger(L, -1);
+        lua_pop(L, 1);
       }
     }
   }
+  else {
+    if (instructionsPercent > 100) {
+      TRACE("Script %8s killed", filename);
+      sid.state = SCRIPT_KILLED;
+    }
+    else {
+      TRACE("Script %8s error: %s", filename, lua_tostring(L, -1));
+      sid.state = SCRIPT_SYNTAX_ERROR;
+    }
+  }
+
+  if (sid.state != SCRIPT_OK) {
+    luaFree(sid);
+  }
+  else {
+    if (instructionsPercent > sid.instructions) {
+      sid.instructions = instructionsPercent;
+    }
+  }
+  return true;
 }
 
 void luaDoGc()
@@ -1924,6 +1948,103 @@ void luaDoGc()
   }
 }
 
+
+uint32_t lastRunTime;
+
+void luaRunNonGuiScripts()
+{
+  //execute one cycle of all Lua cripts that don't use LCD (model scripts, function scripts)
+
+  uint32_t t0 = get_tmr10ms();
+  static uint32_t lastLuaTime = 0;
+  uint16_t interval = (lastLuaTime == 0 ? 0 : (t0 - lastLuaTime));
+  lastLuaTime = t0;
+  if (interval > maxLuaInterval) {
+    maxLuaInterval = interval;
+  }
+
+  luaLcdAllowed = false;
+  if (luaState == INTERPRETER_PANIC) return;
+  if (luaState & INTERPRETER_RUNNING_STANDALONE_SCRIPT) return;
+
+  if (luaState & INTERPRETER_RELOAD_PERMANENT_SCRIPTS) {
+    luaState = 0;
+    luaInit();
+    if (luaState == INTERPRETER_PANIC) return;
+    luaLoadPermanentScripts();
+    if (luaState == INTERPRETER_PANIC) return;
+  }
+  for (int i=0; i<luaScriptsCount; i++) {
+    PROTECT_LUA() {
+      luaDoOneRunPermanentScript(0, i, false);
+    }
+    else {
+      luaDisable();
+      return;
+    }
+    UNPROTECT_LUA();
+    //todo gc step between scripts
+  }
+  luaDoGc();
+
+  lastRunTime = get_tmr10ms() - t0;
+}
+
+bool luaRunGuiScripts(uint8_t evt){
+  //execute one cycle of Lua scripts that use LCD
+  //either stand-alone or other (telemetry scripts)
+
+  uint32_t t0 = get_tmr10ms();
+
+
+  luaLcdAllowed = true;
+  if (luaState == INTERPRETER_PANIC) return false;
+
+  bool scriptWasRun = false;
+  if (luaState & INTERPRETER_RUNNING_STANDALONE_SCRIPT) {
+    PROTECT_LUA() {
+      luaDoOneRunStandalone(evt);
+      scriptWasRun = true;
+    }
+    else {
+      luaDisable();
+      return false;
+    }
+    UNPROTECT_LUA();
+  }
+  else {
+    // model scripts
+    if (luaState & INTERPRETER_RELOAD_PERMANENT_SCRIPTS) {
+      luaState = 0;
+      luaInit();
+      if (luaState == INTERPRETER_PANIC) return false;
+      luaLoadPermanentScripts();
+      if (luaState == INTERPRETER_PANIC) return false;
+    }
+
+    for (int i=0; i<luaScriptsCount; i++) {
+      PROTECT_LUA() {
+        scriptWasRun |= luaDoOneRunPermanentScript(evt, i, true);
+      }
+      else {
+        luaDisable();
+        return false;
+      }
+      UNPROTECT_LUA();
+      //todo gc step between scripts
+    }
+  }
+  luaDoGc();
+
+  lastRunTime += get_tmr10ms() - t0;
+  if (lastRunTime > maxLuaDuration) {
+    maxLuaDuration = lastRunTime;
+  }
+
+  return scriptWasRun;
+}
+
+#if 0
 void luaTask(uint8_t evt)
 {
   uint32_t t0 = get_tmr10ms();
@@ -1977,6 +2098,7 @@ void luaTask(uint8_t evt)
     maxLuaDuration = t0;
   }
 }
+#endif
 
 int luaGetMemUsed()
 {
diff --git a/radio/src/lua_api.h b/radio/src/lua_api.h
new file mode 100644
index 000000000..6df19f118
--- /dev/null
+++ b/radio/src/lua_api.h
@@ -0,0 +1,128 @@
+/*
+ * Authors (alphabetical order)
+ * - Andre Bernet <bernet.andre@gmail.com>
+ * - Andreas Weitl
+ * - Bertrand Songis <bsongis@gmail.com>
+ * - Bryan J. Rentoul (Gruvin) <gruvin@gmail.com>
+ * - Cameron Weeks <th9xer@gmail.com>
+ * - Erez Raviv
+ * - Gabriel Birkus
+ * - Jean-Pierre Parisy
+ * - Karl Szmutny
+ * - Michael Blandford
+ * - Michal Hlavinka
+ * - Pat Mackenzie
+ * - Philip Moss
+ * - Rob Thomson
+ * - Romolo Manfredini <romolo.manfredini@gmail.com>
+ * - Thomas Husterer
+ *
+ * opentx is based on code named
+ * gruvin9x by Bryan J. Rentoul: http://code.google.com/p/gruvin9x/,
+ * er9x by Erez Raviv: http://code.google.com/p/er9x/,
+ * and the original (and ongoing) project by
+ * Thomas Husterer, th9x: http://code.google.com/p/th9x/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef luaapi_h
+#define luaapi_h
+
+
+
+#if defined(LUA)
+  struct ScriptInput {
+    const char *name;
+    uint8_t type;
+    int16_t min;
+    int16_t max;
+    int16_t def;
+  };
+  struct ScriptOutput {
+    const char *name;
+    int16_t value;
+  };
+  enum ScriptState {
+    SCRIPT_OK,
+    SCRIPT_NOFILE,
+    SCRIPT_SYNTAX_ERROR,
+    SCRIPT_PANIC,
+    SCRIPT_KILLED
+  };
+  enum ScriptReference {
+    SCRIPT_MIX_FIRST,
+    SCRIPT_MIX_LAST=SCRIPT_MIX_FIRST+MAX_SCRIPTS-1,
+    SCRIPT_FUNC_FIRST,
+    SCRIPT_FUNC_LAST=SCRIPT_FUNC_FIRST+NUM_CFN-1,
+    SCRIPT_TELEMETRY_FIRST,
+    SCRIPT_TELEMETRY_LAST=SCRIPT_TELEMETRY_FIRST+MAX_SCRIPTS, // telem0 and telem1 .. telem7
+  };
+  struct ScriptInternalData {
+    uint8_t reference;
+    uint8_t state;
+    int run;
+    int background;
+    uint8_t instructions;
+  };
+  struct ScriptInputsOutputs {
+    uint8_t inputsCount;
+    ScriptInput inputs[MAX_SCRIPT_INPUTS];
+    uint8_t outputsCount;
+    ScriptOutput outputs[MAX_SCRIPT_OUTPUTS];
+  };
+  #define INTERPRETER_RUNNING_STANDALONE_SCRIPT 1
+  #define INTERPRETER_RELOAD_PERMANENT_SCRIPTS  2
+  #define INTERPRETER_PANIC                     255
+  extern uint8_t luaState;
+  extern uint8_t luaScriptsCount;
+  extern ScriptInternalData standaloneScript;
+  extern ScriptInternalData scriptInternalData[MAX_SCRIPTS];
+  extern ScriptInputsOutputs scriptInputsOutputs[MAX_SCRIPTS];
+  void luaClose();
+  // void luaInit();
+  // void luaTask(uint8_t evt);
+  void luaExec(const char *filename);
+  int luaGetMemUsed();
+  #define luaGetCpuUsed(idx) scriptInternalData[idx].instructions
+  #define LUA_LOAD_MODEL_SCRIPTS()   luaState |= INTERPRETER_RELOAD_PERMANENT_SCRIPTS
+  #define LUA_LOAD_MODEL_SCRIPT(idx) luaState |= INTERPRETER_RELOAD_PERMANENT_SCRIPTS
+  #define LUA_STANDALONE_SCRIPT_RUNNING() (luaState == INTERPRETER_RUNNING_STANDALONE_SCRIPT)
+  // Lua PROTECT/UNPROTECT
+  #include <setjmp.h>
+  struct our_longjmp {
+    struct our_longjmp *previous;
+    jmp_buf b;
+    volatile int status;  /* error code */
+  };
+  extern struct our_longjmp * global_lj;
+  #define PROTECT_LUA()   { struct our_longjmp lj; \
+                          lj.previous = global_lj;  /* chain new error handler */ \
+                          global_lj = &lj;  \
+                          if (setjmp(lj.b) == 0)
+  #define UNPROTECT_LUA() global_lj = lj.previous; }   /* restore old error handler */
+
+  void luaRunNonGuiScripts();
+  bool luaRunGuiScripts(uint8_t evt);
+
+  extern uint16_t maxLuaInterval;
+  extern uint16_t maxLuaDuration;
+
+
+#else  // #if defined(LUA)
+  #define LUA_LOAD_MODEL_SCRIPTS()
+  #define LUA_LOAD_MODEL_SCRIPT(idx)
+  #define LUA_STANDALONE_SCRIPT_RUNNING() (0)
+  #define luaRunNonGuiScripts()
+  #define luaRunGuiScripts(evt)   (false)
+#endif
+
+#endif // #ifndef luaapi_h
diff --git a/radio/src/opentx.cpp b/radio/src/opentx.cpp
index b0dd96212..7453e0822 100644
--- a/radio/src/opentx.cpp
+++ b/radio/src/opentx.cpp
@@ -2136,7 +2136,7 @@ uint8_t getSticksNavigationEvent()
 }
 #endif
 
-void batteryCheck()
+void checkBattery()
 {
   static uint8_t counter = 0;
   if (g_menuStack[g_menuStackPtr] == menuGeneralDiagAna) {
@@ -2327,7 +2327,7 @@ void perMain()
     JACK_PPM_IN();
   }
 
-  batteryCheck();
+  checkBattery();
 }
 #endif   // #if !defined(CPUARM)
 
diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 3ae32273d..1e25023fe 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -922,11 +922,6 @@ extern uint8_t g_tmr1Latency_min;
 extern uint16_t lastMixerDuration;
 #endif
 
-#if defined(LUA)
-extern uint16_t maxLuaInterval;
-extern uint16_t maxLuaDuration;
-#endif
-
 #if defined(CPUARM)
   #define DURATION_MS_PREC2(x) ((x)/20)
 #else
@@ -1536,82 +1531,6 @@ enum AUDIO_SOUNDS {
 #include "rtc.h"
 #endif
 
-#if defined(LUA)
-  struct ScriptInput {
-    const char *name;
-    uint8_t type;
-    int16_t min;
-    int16_t max;
-    int16_t def;
-  };
-  struct ScriptOutput {
-    const char *name;
-    int16_t value;
-  };
-  enum ScriptState {
-    SCRIPT_OK,
-    SCRIPT_NOFILE,
-    SCRIPT_SYNTAX_ERROR,
-    SCRIPT_PANIC,
-    SCRIPT_KILLED
-  };
-  enum ScriptReference {
-    SCRIPT_MIX_FIRST,
-    SCRIPT_MIX_LAST=SCRIPT_MIX_FIRST+MAX_SCRIPTS-1,
-    SCRIPT_FUNC_FIRST,
-    SCRIPT_FUNC_LAST=SCRIPT_FUNC_FIRST+NUM_CFN-1,
-    SCRIPT_TELEMETRY_FIRST,
-    SCRIPT_TELEMETRY_LAST=SCRIPT_TELEMETRY_FIRST+MAX_SCRIPTS, // telem0 and telem1 .. telem7
-  };
-  struct ScriptInternalData {
-    uint8_t reference;
-    uint8_t state;
-    int run;
-    int background;
-    uint8_t instructions;
-  };
-  struct ScriptInputsOutputs {
-    uint8_t inputsCount;
-    ScriptInput inputs[MAX_SCRIPT_INPUTS];
-    uint8_t outputsCount;
-    ScriptOutput outputs[MAX_SCRIPT_OUTPUTS];
-  };
-  #define INTERPRETER_RUNNING_STANDALONE_SCRIPT 1
-  #define INTERPRETER_RELOAD_PERMANENT_SCRIPTS  2
-  #define INTERPRETER_PANIC                     255
-  extern uint8_t luaState;
-  extern uint8_t luaScriptsCount;
-  extern ScriptInternalData standaloneScript;
-  extern ScriptInternalData scriptInternalData[MAX_SCRIPTS];
-  extern ScriptInputsOutputs scriptInputsOutputs[MAX_SCRIPTS];
-  void luaClose();
-  void luaInit();
-  void luaTask(uint8_t evt);
-  void luaExec(const char *filename);
-  int luaGetMemUsed();
-  #define luaGetCpuUsed(idx) scriptInternalData[idx].instructions
-  #define LUA_LOAD_MODEL_SCRIPTS()   luaState |= INTERPRETER_RELOAD_PERMANENT_SCRIPTS
-  #define LUA_LOAD_MODEL_SCRIPT(idx) luaState |= INTERPRETER_RELOAD_PERMANENT_SCRIPTS
-  #define LUA_STANDALONE_SCRIPT_RUNNING() (luaState == INTERPRETER_RUNNING_STANDALONE_SCRIPT)
-  // Lua PROTECT/UNPROTECT
-  #include <setjmp.h>
-  struct our_longjmp {
-    struct our_longjmp *previous;
-    jmp_buf b;
-    volatile int status;  /* error code */
-  };
-  extern struct our_longjmp * global_lj;
-  #define PROTECT_LUA()   { struct our_longjmp lj; \
-                          lj.previous = global_lj;  /* chain new error handler */ \
-                          global_lj = &lj;  \
-                          if (setjmp(lj.b) == 0)
-  #define UNPROTECT_LUA() global_lj = lj.previous; }   /* restore old error handler */
-#else
-  #define LUA_LOAD_MODEL_SCRIPTS()
-  #define LUA_LOAD_MODEL_SCRIPT(idx)
-  #define LUA_STANDALONE_SCRIPT_RUNNING() (0)
-#endif
-
 #if defined(CPUARM)
 extern uint8_t requiredSpeakerVolume;
 #endif
@@ -1826,4 +1745,6 @@ void varioWakeup();
   extern void usbPluggedIn();
 #endif
 
+#include "lua_api.h"
+
 #endif
diff --git a/radio/src/targets/taranis/keys_driver.cpp b/radio/src/targets/taranis/keys_driver.cpp
index 7437d2cfb..6c36d5e46 100644
--- a/radio/src/targets/taranis/keys_driver.cpp
+++ b/radio/src/targets/taranis/keys_driver.cpp
@@ -41,11 +41,8 @@
 uint32_t readKeys()
 {
   register uint32_t d = GPIOD->IDR;
-#if !defined(REV9E)
   register uint32_t e = GPIOE->IDR;
-#else
   register uint32_t f = GPIOF->IDR;
-#endif
   register uint32_t result = 0;
 
 #if defined(REV9E)
@@ -55,7 +52,7 @@ uint32_t readKeys()
 #endif
     result |= 0x02 << KEY_ENTER;
 
-#if !defined(REV9E)
+#if !defined(REV9E) || defined(SIMU)
   if (e & PIN_BUTTON_PLUS)
     result |= 0x02 << KEY_PLUS;
   if (e & PIN_BUTTON_MINUS)
diff --git a/radio/src/tasks_arm.cpp b/radio/src/tasks_arm.cpp
index 8883b6fcc..6e2ae7dd8 100644
--- a/radio/src/tasks_arm.cpp
+++ b/radio/src/tasks_arm.cpp
@@ -36,11 +36,10 @@
 
 #include "opentx.h"
 
-
 static uint8_t currentSpeakerVolume = 255;
 uint8_t requiredSpeakerVolume;
 
-extern void batteryCheck();
+extern void checkBattery();
 
 void handleUsbConnection()
 {
@@ -109,6 +108,7 @@ void perMainArm()
   writeLogs();
   handleUsbConnection();
   checkTrainerSettings();
+  checkBattery();
 
   uint8_t evt = getEvent(false);
   if (evt && (g_eeGeneral.backlightMode & e_backlight_mode_keys)) backlightOn(); // on keypress turn the light on
@@ -118,49 +118,47 @@ void perMainArm()
   if (sticks_evt) evt = sticks_evt;
 #endif
 
-
 #if defined(USB_MASS_STORAGE)
   if (usbPlugged()) {
+    // disable access to menus
     lcd_clear();
     menuMainView(0);
+    lcdRefresh();
+    return;
   }
-  else 
 #endif
-  {
+
+  // run Lua scripts that don't use LCD (to use CPU time while LCD DMA is running)
+  luaRunNonGuiScripts();
+
+  // draw LCD from menus or from Lua script
+  if (luaRunGuiScripts(evt)) {   // either stand-alone or telemetry scripts
+    // let Lua manage LCD fully
+  }
+  else {
+    // normal GUI from menus
     const char *warn = s_warning;
     uint8_t menu = s_menu_count;
-
-    if (!LUA_STANDALONE_SCRIPT_RUNNING()) {
-      lcd_clear();
-      if (menuEvent) {
-        m_posVert = menuEvent == EVT_ENTRY_UP ? g_menuPos[g_menuStackPtr] : 0;
-        m_posHorz = 0;
-        evt = menuEvent;
-        menuEvent = 0;
-        AUDIO_MENUS();
-      }
-      g_menuStack[g_menuStackPtr]((warn || menu) ? 0 : evt);
+    lcd_clear();
+    if (menuEvent) {
+      m_posVert = menuEvent == EVT_ENTRY_UP ? g_menuPos[g_menuStackPtr] : 0;
+      m_posHorz = 0;
+      evt = menuEvent;
+      menuEvent = 0;
+      AUDIO_MENUS();
     }
-
-#if defined(LUA)
-    luaTask(evt);
-#endif
-
-    if (!LUA_STANDALONE_SCRIPT_RUNNING()) {
-      if (warn) DISPLAY_WARNING(evt);
-      if (menu) {
-        const char * result = displayMenu(evt);
-        if (result) {
-          menuHandler(result);
-          putEvent(EVT_MENU_UP);
-        }
+    g_menuStack[g_menuStackPtr]((warn || menu) ? 0 : evt);
+    if (warn) DISPLAY_WARNING(evt);
+    if (menu) {
+      const char * result = displayMenu(evt);
+      if (result) {
+        menuHandler(result);
+        putEvent(EVT_MENU_UP);
       }
     }
+    drawStatusLine();
   }
-
-  drawStatusLine();
   lcdRefresh();
-  batteryCheck();
 }
 
 #define MENUS_STACK_SIZE    2000
diff --git a/radio/src/tests/gtests.h b/radio/src/tests/gtests.h
index 43c780b4a..eff8915d7 100644
--- a/radio/src/tests/gtests.h
+++ b/radio/src/tests/gtests.h
@@ -42,8 +42,10 @@ inline void MIXER_RESET()
 
 inline void TELEMETRY_RESET()
 {
+#if defined(FRSKY)
   memclear(&frskyData, sizeof(frskyData));
   TELEMETRY_RSSI() = 100;
+#endif
 }
 
 void MIXER_RESET();
diff --git a/radio/src/tests/lua.cpp b/radio/src/tests/lua.cpp
index f4e1c37e1..625a51960 100644
--- a/radio/src/tests/lua.cpp
+++ b/radio/src/tests/lua.cpp
@@ -48,6 +48,7 @@
 
 extern const char * zchar2string(const char * zstring, int size);
 #define EXPECT_ZSTREQ(c_string, z_string)   EXPECT_STREQ(c_string, zchar2string(z_string, sizeof(z_string)))
+extern void luaInit();
 
 void luaExecStr(const char * str)
 {
diff --git a/radio/src/tests/mixer.cpp b/radio/src/tests/mixer.cpp
index 7655e3ac9..2c09886fc 100644
--- a/radio/src/tests/mixer.cpp
+++ b/radio/src/tests/mixer.cpp
@@ -391,7 +391,11 @@ TEST(Trims, CopySticksToOffset)
   MODEL_RESET();
   modelDefault(0);
   anaInValues[ELE_STICK] = -100;
+#if defined(CPUARM)
+  doMixerCalculations();
+#else
   perMain();
+#endif
   copySticksToOffset(1);
   EXPECT_EQ(g_model.limitData[1].offset, -97);
 }
@@ -618,11 +622,19 @@ TEST(Mixer, RecursiveAddChannelAfterInactivePhase)
   g_model.mixData[2].srcRaw = MIXSRC_MAX;
   g_model.mixData[2].weight = 100;
   simuSetSwitch(3, -1);
+#if defined(CPUARM)
+  doMixerCalculations();
+#else
   perMain();
+#endif
   EXPECT_EQ(chans[0], CHANNEL_MAX/2);
   EXPECT_EQ(chans[1], CHANNEL_MAX);
   simuSetSwitch(3, 0);
+#if defined(CPUARM)
+  doMixerCalculations();
+#else
   perMain();
+#endif
   EXPECT_EQ(chans[0], CHANNEL_MAX/2);
   EXPECT_EQ(chans[1], CHANNEL_MAX);
 }