diff --git a/radio/src/audio_arm.cpp b/radio/src/audio_arm.cpp
index f4e9e8db1..84eb6d70f 100644
--- a/radio/src/audio_arm.cpp
+++ b/radio/src/audio_arm.cpp
@@ -497,16 +497,13 @@ void audioTask(void * pdata)
 
   setSampleRate(AUDIO_SAMPLE_RATE);
 
-#if !defined(EEPROM)
-  AUDIO_HELLO();
-#elif defined(SDCARD)
+  while (!sdMounted()) {
+    CoTickDelay(10);
+  }
+  
   if (!unexpectedShutdown) {
-#if defined(EEPROM)
-    sdInit();
-#endif
     AUDIO_HELLO();
   }
-#endif
 
   while (1) {
     audioQueue.wakeup();
diff --git a/radio/src/main_arm.cpp b/radio/src/main_arm.cpp
index 4d945935d..724cb73c6 100644
--- a/radio/src/main_arm.cpp
+++ b/radio/src/main_arm.cpp
@@ -54,6 +54,9 @@ void handleUsbConnection()
   }
   if (usbStarted && !usbPlugged()) {
     usbStarted = false;
+#if defined(USB_MASS_STORAGE) && !defined(EEPROM)
+    opentxResume();
+#endif
   }
 
 #if defined(USB_JOYSTICK)
diff --git a/radio/src/opentx.cpp b/radio/src/opentx.cpp
index e5660658d..2d3fda029 100644
--- a/radio/src/opentx.cpp
+++ b/radio/src/opentx.cpp
@@ -1912,19 +1912,28 @@ uint8_t calcStickScroll( uint8_t index )
 }
 #endif
 
-void opentxStart()
-{
-  TRACE("opentxStart()");
-
-#if defined(SIMU)
-  if (main_thread_running == 2)
-    return;
+#if defined(CPUARM)
+  #define OPENTX_START_ARGS            uint8_t splash=true
+  #define OPENTX_START_SPLASH_NEEDED() (splash)
+#else
+  #define OPENTX_START_ARGS
+  #define OPENTX_START_SPLASH_NEEDED() true
 #endif
 
-  bool display_alerts = (g_eeGeneral.chkSum == evalChkSum());
+void opentxStart(OPENTX_START_ARGS)
+{
+  TRACE("opentxStart");
+
+#if defined(SIMU)
+  if (main_thread_running == 2) {
+    return;
+  }
+#endif
+
+  uint8_t calibration_needed = (g_eeGeneral.chkSum != evalChkSum());
 
 #if defined(GUI)
-  if (display_alerts) {
+  if (!calibration_needed && OPENTX_START_SPLASH_NEEDED()) {
     doSplash();
   }
 #endif
@@ -1940,12 +1949,12 @@ void opentxStart()
 #endif
 
 #if defined(GUI)
-  if (display_alerts) {
-    checkAlarm();
-    checkAll();
+  if (calibration_needed) {
+    chainMenu(menuFirstCalib);
   }
   else {
-    chainMenu(menuFirstCalib);
+    checkAlarm();
+    checkAll();
   }
 #endif
 }
@@ -1953,7 +1962,7 @@ void opentxStart()
 #if defined(CPUARM) || defined(CPUM2560)
 void opentxClose(uint8_t shutdown)
 {
-  TRACE("opentxClose()");
+  TRACE("opentxClose");
 
   if (shutdown) {
 #if defined(CPUARM)
@@ -2030,6 +2039,33 @@ void opentxClose(uint8_t shutdown)
 }
 #endif
 
+#if defined(USB_MASS_STORAGE)
+void opentxResume()
+{
+  TRACE("opentxResume");
+  
+  menuHandlers[0] = menuMainView;
+  
+  sdMount();
+  
+  storageReadAll();
+
+#if defined(PCBHORUS)
+  loadTheme();
+  loadFontCache();
+#endif
+  
+  opentxStart(false);
+
+#if defined(CPUARM) || defined(CPUM2560)
+  if (!g_eeGeneral.unexpectedShutdown) {
+    g_eeGeneral.unexpectedShutdown = 1;
+    storageDirty(EE_GENERAL);
+  }
+#endif
+}
+#endif
+
 #if defined(NAVIGATION_STICKS)
 uint8_t getSticksNavigationEvent()
 {
@@ -2477,7 +2513,7 @@ void opentxInit(OPENTX_INIT_ARGS)
   // CoTickDelay(5000); // 10s
 #endif
 
-  TRACE("opentxInit()");
+  TRACE("opentxInit");
 
 #if defined(GUI)
   menuHandlers[0] = menuMainView;
@@ -2490,11 +2526,14 @@ void opentxInit(OPENTX_INIT_ARGS)
   rtcInit();    // RTC must be initialized before rambackupRestore() is called
 #endif
 
-#if !defined(EEPROM)
-  if (!UNEXPECTED_SHUTDOWN()) {
-    sdInit();
+  if (UNEXPECTED_SHUTDOWN()) {
+    unexpectedShutdown = 1;
   }
+  else {
+#if defined(SDCARD) && !defined(PCBMEGA2560)
+    sdInit();
 #endif
+  }
 
 #if defined(PCBHORUS)
   topbar = new Topbar(&g_model.topbarData);
@@ -2512,12 +2551,6 @@ void opentxInit(OPENTX_INIT_ARGS)
   storageReadAll();
 #endif
 
-#if defined(CPUARM)
-  if (UNEXPECTED_SHUTDOWN()) {
-    unexpectedShutdown = 1;
-  }
-#endif
-
 #if defined(PCBTARANIS)
   BACKLIGHT_ON();
 #endif
@@ -2554,13 +2587,7 @@ void opentxInit(OPENTX_INIT_ARGS)
 
   if (g_eeGeneral.backlightMode != e_backlight_mode_off) backlightOn(); // on Tx start turn the light on
 
-  if (UNEXPECTED_SHUTDOWN()) {
-#if !defined(CPUARM)
-    // is done above on ARM
-    unexpectedShutdown = 1;
-#endif
-  }
-  else {
+  if (!UNEXPECTED_SHUTDOWN()) {
     opentxStart();
   }
 
diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 857ac0b2a..3a34506ec 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -1426,6 +1426,7 @@ extern uint8_t requestScreenshot;
 void checkBattery();
 void opentxClose(uint8_t shutdown=true);
 void opentxInit();
+void opentxResume();
 
 #if defined(PCBHORUS) && !defined(SIMU)
   #define LED_ERROR_BEGIN()            ledRed()
@@ -1704,7 +1705,7 @@ FORCEINLINE void convertUnit(getvalue_t & val, uint8_t & unit)
 #endif
 
 #if defined(USB_MASS_STORAGE)
-  extern void usbPluggedIn();
+void usbPluggedIn();
 #endif
 
 #include "lua/lua_api.h"
diff --git a/radio/src/storage/eeprom_common.cpp b/radio/src/storage/eeprom_common.cpp
index 2d58a9e60..8dd249caf 100644
--- a/radio/src/storage/eeprom_common.cpp
+++ b/radio/src/storage/eeprom_common.cpp
@@ -44,14 +44,14 @@ void eeLoadModel(uint8_t index)
     }
 #endif
 
-    bool newModel = false;
+    bool alarms = true;
     if (size < EEPROM_MIN_MODEL_SIZE) { // if not loaded a fair amount
       modelDefault(index) ;
       storageCheck(true);
-      newModel = true;
+      alarms = false;
     }
 
-    postModelLoad(newModel);
+    postModelLoad(alarms);
   }
 }
 
diff --git a/radio/src/storage/eeprom_rlc.h b/radio/src/storage/eeprom_rlc.h
index c1b55d910..628341af6 100644
--- a/radio/src/storage/eeprom_rlc.h
+++ b/radio/src/storage/eeprom_rlc.h
@@ -234,7 +234,7 @@ const pm_char * eeRestoreModel(uint8_t i_fileDst, char *model_name);
 // For conversions
 #if defined(CPUARM)
 void loadGeneralSettings();
-void loadModel(int index);
+void loadModel(int index, bool alarms=true);
 #endif
 
 bool eepromOpen();
diff --git a/radio/src/storage/sdcard_raw.cpp b/radio/src/storage/sdcard_raw.cpp
index 3941b96cf..5a6a51b6e 100644
--- a/radio/src/storage/sdcard_raw.cpp
+++ b/radio/src/storage/sdcard_raw.cpp
@@ -29,6 +29,8 @@ void getModelPath(char * path, const char * filename)
 
 const char * writeFile(const char * filename, const uint8_t * data, uint16_t size)
 {
+  TRACE("writeFile(%s)", filename);
+  
   FIL file;
   char buf[8];
   UINT written;
@@ -68,6 +70,8 @@ const char * writeModel()
 
 const char * loadFile(const char * filename, uint8_t * data, uint16_t maxsize)
 {
+  TRACE("loadFile(%s)", filename);
+  
   FIL file;
   char buf[8];
   UINT read;
@@ -112,7 +116,7 @@ const char * readModel(const char * filename, uint8_t * buffer, uint32_t size)
   return loadFile(path, buffer, size);
 }
 
-const char * loadModel(const char * filename)
+const char * loadModel(const char * filename, bool alarms)
 {
   preModelLoad();
 
@@ -120,15 +124,14 @@ const char * loadModel(const char * filename)
   if (error) {
     TRACE("loadModel error=%s", error);
   }
-
-  bool newModel = false;
+  
   if (error) {
     modelDefault(0) ;
     storageCheck(true);
-    newModel = true;
+    alarms = false;
   }
 
-  postModelLoad(newModel);
+  postModelLoad(alarms);
 
   return error;
 }
@@ -171,8 +174,8 @@ void storageCheck(bool immediately)
 
 void storageReadAll()
 {
-  sdInit();
-
+  TRACE("storageReadAll");
+  
   if (loadGeneralSettings() != NULL) {
     storageEraseAll(true);
   }
@@ -186,7 +189,7 @@ void storageReadAll()
   }
 #endif
 
-  loadModel(g_eeGeneral.currModelFilename);
+  loadModel(g_eeGeneral.currModelFilename, false);
 }
 
 void storageCreateModelsList()
@@ -223,14 +226,14 @@ const char * createModel()
     storageDirty(EE_MODEL);
     storageCheck(true);
   }
-  postModelLoad(true);
+  postModelLoad(false);
 
   return g_eeGeneral.currModelFilename;
 }
 
 void storageEraseAll(bool warn)
 {
-  TRACE("storageEraseAll()");
+  TRACE("storageEraseAll");
 
 #if defined(COLORLCD)
   // the theme has not been loaded before
diff --git a/radio/src/storage/sdcard_raw.h b/radio/src/storage/sdcard_raw.h
index 0043a2970..628b53eff 100644
--- a/radio/src/storage/sdcard_raw.h
+++ b/radio/src/storage/sdcard_raw.h
@@ -27,7 +27,7 @@
 #define DEFAULT_MODEL_FILENAME   "model01.bin"
 
 const char * readModel(const char * filename, uint8_t * buffer, uint32_t size);
-const char * loadModel(const char * filename);
+const char * loadModel(const char * filename, bool alarms=true);
 const char * createModel();
 
 PACK(struct RamBackup {
diff --git a/radio/src/storage/storage.h b/radio/src/storage/storage.h
index a6edc533f..ccc5966ca 100644
--- a/radio/src/storage/storage.h
+++ b/radio/src/storage/storage.h
@@ -52,7 +52,7 @@ void storageDirty(uint8_t msk);
 void storageCheck(bool immediately);
 
 void preModelLoad();
-void postModelLoad(bool newModel);
+void postModelLoad(bool alarms);
 
 #if defined(EEPROM_RLC)
 #include "eeprom_common.h"
diff --git a/radio/src/storage/storage_common.cpp b/radio/src/storage/storage_common.cpp
index a0beb637e..c9ecb2ddf 100644
--- a/radio/src/storage/storage_common.cpp
+++ b/radio/src/storage/storage_common.cpp
@@ -56,14 +56,14 @@ void preModelLoad()
   pauseMixerCalculations();
 }
 
-void postModelLoad(bool newModel)
+void postModelLoad(bool alarms)
 {
   AUDIO_FLUSH();
   flightReset(false);
 
   if (pulsesStarted()) {
 #if defined(GUI)
-    if (!newModel) {
+    if (alarms) {
       checkAll();
     }
 #endif
diff --git a/radio/src/targets/horus/board.cpp b/radio/src/targets/horus/board.cpp
index 531e94e2a..426b9142a 100644
--- a/radio/src/targets/horus/board.cpp
+++ b/radio/src/targets/horus/board.cpp
@@ -149,7 +149,7 @@ void boardInit()
 
   __enable_irq();
 
-  TRACE("Horus started :)");
+  TRACE("\nHorus board started :)");
 
   keysInit();
   adcInit();
diff --git a/radio/src/targets/horus/board.h b/radio/src/targets/horus/board.h
index 0d1169afb..e5e514bb5 100644
--- a/radio/src/targets/horus/board.h
+++ b/radio/src/targets/horus/board.h
@@ -109,6 +109,7 @@ uint32_t sdGetSpeed(void);
 #define SD_GET_FREE_BLOCKNR()          (sdGetFreeSectors())
 #define SD_CARD_PRESENT()              (~SD_PRESENT_GPIO->IDR & SD_PRESENT_GPIO_PIN)
 void sdInit(void);
+void sdMount(void);
 void sdDone(void);
 #define sdPoll10ms()
 #define sdMountPoll()
diff --git a/radio/src/targets/horus/diskio.cpp b/radio/src/targets/horus/diskio.cpp
index 37d16829a..fe931ab06 100644
--- a/radio/src/targets/horus/diskio.cpp
+++ b/radio/src/targets/horus/diskio.cpp
@@ -292,14 +292,22 @@ FATFS g_FATFS_Obj __DMA;
 FIL g_telemetryFile = {0};
 #endif
 
-void sdInit(void)
+void sdInit()
 {
+  TRACE("sdInit");
+  
   ioMutex = CoCreateMutex();
-  if (ioMutex >= CFG_MAX_MUTEX ) {
+  if (ioMutex >= CFG_MAX_MUTEX) {
     // sd error
     return;
   }
+  sdMount();
+}
 
+void sdMount()
+{
+  TRACE("sdMount");
+  
   if (f_mount(&g_FATFS_Obj, "", 1) == FR_OK) {
     // call sdGetFreeSectors() now because f_getfree() takes a long time first time it's called
     sdGetFreeSectors();
@@ -320,6 +328,8 @@ void sdInit(void)
 
 void sdDone()
 {
+  TRACE("sdDone");
+  
   if (sdMounted()) {
     audioQueue.stopSD();
 #if defined(LOG_TELEMETRY)
diff --git a/radio/src/targets/sky9x/diskio.cpp b/radio/src/targets/sky9x/diskio.cpp
index 0a590eaad..ecc52bdbe 100644
--- a/radio/src/targets/sky9x/diskio.cpp
+++ b/radio/src/targets/sky9x/diskio.cpp
@@ -843,6 +843,8 @@ const char * sdEnum()
 
 void sdInit()
 {
+  TRACE("sdInit");
+  
   const char * result;
   uint8_t i;
 
diff --git a/radio/src/targets/taranis/bootloader/boot.cpp b/radio/src/targets/taranis/bootloader/boot.cpp
index 96ed2d3bd..0e795f563 100644
--- a/radio/src/targets/taranis/bootloader/boot.cpp
+++ b/radio/src/targets/taranis/bootloader/boot.cpp
@@ -151,9 +151,9 @@ uint32_t unlocked = 0;
 
 extern uint32_t EepromBlocked;
 
-extern void init_spi(void);
-extern void writeBlock(void);
-extern void usbPluggedIn();
+void init_spi(void);
+void writeBlock(void);
+void usbPluggedIn();
 
 #if defined(PCBX9E)
 typedef int32_t rotenc_t;
diff --git a/radio/src/targets/taranis/diskio.cpp b/radio/src/targets/taranis/diskio.cpp
index 004f2d12e..b5b9aadfc 100644
--- a/radio/src/targets/taranis/diskio.cpp
+++ b/radio/src/targets/taranis/diskio.cpp
@@ -992,6 +992,8 @@ void sdInit(void)
 // TODO shouldn't be there!
 void sdInit(void)
 {
+  TRACE("sdInit");
+  
   ioMutex = CoCreateMutex();
   if (ioMutex >= CFG_MAX_MUTEX ) {
     //sd error