diff --git a/radio/src/dataconstants.h b/radio/src/dataconstants.h
index 803261c6b1..0052b0f6a6 100644
--- a/radio/src/dataconstants.h
+++ b/radio/src/dataconstants.h
@@ -191,8 +191,8 @@ enum TrainerMode {
 #if defined(PCBTARANIS)
   TRAINER_MODE_MASTER_SBUS_EXTERNAL_MODULE,
   TRAINER_MODE_MASTER_CPPM_EXTERNAL_MODULE,
-#endif
   TRAINER_MODE_MASTER_BATTERY_COMPARTMENT,
+#endif
 #if defined(BLUETOOTH)
   TRAINER_MODE_MASTER_BLUETOOTH,
   TRAINER_MODE_SLAVE_BLUETOOTH,
diff --git a/radio/src/gui/gui_common.cpp b/radio/src/gui/gui_common.cpp
index 1086d2b223..52dc9fd183 100644
--- a/radio/src/gui/gui_common.cpp
+++ b/radio/src/gui/gui_common.cpp
@@ -711,7 +711,7 @@ bool isTrainerModeAvailable(int mode)
     return false;
 #endif
 
-#if !defined(PCBSKY9X) && !defined(TRAINER_BATTERY_COMPARTMENT)
+#if defined(PCBTARANIS) && !defined(TRAINER_BATTERY_COMPARTMENT)
   if (mode == TRAINER_MODE_MASTER_BATTERY_COMPARTMENT)
     return false;
 #endif
diff --git a/radio/src/storage/conversions/conversions_218_219.cpp b/radio/src/storage/conversions/conversions_218_219.cpp
index a6d50ba854..0f2c6de9c4 100644
--- a/radio/src/storage/conversions/conversions_218_219.cpp
+++ b/radio/src/storage/conversions/conversions_218_219.cpp
@@ -123,6 +123,10 @@ void convertModelData_218_to_219(ModelData &model)
   // 4 bytes more for the ModelHeader::bitmap
   memclear(&newModel.header.bitmap[10], 4);
   memcpy(newModel.timers, oldModel.timers, offsetof(ModelData_v218, mixData) - offsetof(ModelData_v218, timers));
+
+  // trainer battery compartment removed
+  if (newModel.trainerData.mode >= TRAINER_MODE_MASTER_BLUETOOTH)
+    newModel.trainerData.mode -= 1;
 #endif
 
   memclear(newModel.mixData, sizeof(ModelData_v219) - offsetof(ModelData_v219, mixData));
diff --git a/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp b/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
index fc41ae08b7..1f22abc482 100644
--- a/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
@@ -183,4 +183,4 @@ extern "C" void AUX_SERIAL_USART_IRQHandler(void)
   }
 #endif
 }
-#endif
+#endif
\ No newline at end of file
diff --git a/radio/src/targets/common/arm/stm32/bootloader/boot.cpp b/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
index 0e4b037999..e5adcd5452 100644
--- a/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
+++ b/radio/src/targets/common/arm/stm32/bootloader/boot.cpp
@@ -233,7 +233,7 @@ int main()
 
   delaysInit(); // needed for lcdInit()
 
-#if defined(DEBUG)
+#if defined(DEBUG) && defined(AUX_SERIAL)
   auxSerialInit(UART_MODE_DEBUG, 0); // default serial mode (None if DEBUG not defined)
 #endif
 
diff --git a/radio/src/targets/horus/CMakeLists.txt b/radio/src/targets/horus/CMakeLists.txt
index dc43590920..1184262650 100644
--- a/radio/src/targets/horus/CMakeLists.txt
+++ b/radio/src/targets/horus/CMakeLists.txt
@@ -70,7 +70,6 @@ elseif (PCB STREQUAL X12S)
     x12s_adc_driver.cpp
     gps_driver.cpp
     )
-  set(AUX_SERIAL_DRIVER ../common/arm/stm32/aux_serial_driver.cpp)
   set(BITMAPS_TARGET x12s_bitmaps)
   set(FONTS_TARGET x12s_fonts)
   set(LCD_DRIVER lcd_driver.cpp)
diff --git a/radio/src/targets/horus/board.cpp b/radio/src/targets/horus/board.cpp
index 85530ece28..40900a0995 100644
--- a/radio/src/targets/horus/board.cpp
+++ b/radio/src/targets/horus/board.cpp
@@ -128,10 +128,6 @@ void boardInit()
   pwrOn();
   delaysInit();
 
-#if defined(DEBUG)
-  auxSerialInit(0, 0); // default serial mode (None if DEBUG not defined)
-#endif
-
   __enable_irq();
 
   TRACE("\nHorus board started :)");
diff --git a/radio/src/targets/horus/board.h b/radio/src/targets/horus/board.h
index 0cb3ed9081..13717068a4 100644
--- a/radio/src/targets/horus/board.h
+++ b/radio/src/targets/horus/board.h
@@ -586,17 +586,6 @@ void gpsSendByte(uint8_t byte);
 #define PILOTPOS_MIN_HDOP             500
 #endif
 
-// Second serial port driver
-#if defined(PCBX12S)
-#define AUX_SERIAL
-#define DEBUG_BAUDRATE                 115200
-extern uint8_t auxSerialMode;
-void auxSerialInit(unsigned int mode, unsigned int protocol);
-void auxSerialPutc(char c);
-#define auxSerialTelemetryInit(protocol) auxSerialInit(UART_MODE_TELEMETRY, protocol)
-void auxSerialSbusInit();
-void auxSerialStop();
-#endif
 #define USART_FLAG_ERRORS              (USART_FLAG_ORE | USART_FLAG_NE | USART_FLAG_FE | USART_FLAG_PE)
 
 // BT driver
diff --git a/radio/src/translations/untranslated.h b/radio/src/translations/untranslated.h
index c10c3e3953..65146067e3 100644
--- a/radio/src/translations/untranslated.h
+++ b/radio/src/translations/untranslated.h
@@ -72,7 +72,7 @@
 #endif
 
 #if defined(PCBHORUS)
-  #define TR_VTRAINERMODES             TR_VTRAINER_MASTER_JACK TR_VTRAINER_SLAVE_JACK TR_VTRAINER_MASTER_BATTERY TR_VTRAINER_BLUETOOTH
+  #define TR_VTRAINERMODES             TR_VTRAINER_MASTER_JACK TR_VTRAINER_SLAVE_JACK TR_VTRAINER_BLUETOOTH
 #elif defined(PCBX9E)
   #define TR_VTRAINERMODES             TR_VTRAINER_MASTER_JACK TR_VTRAINER_SLAVE_JACK TR_VTRAINER_MASTER_SBUS_MODULE TR_VTRAINER_MASTER_CPPM_MODULE TR_VTRAINER_MASTER_BATTERY TR_VTRAINER_BLUETOOTH
 #elif defined(PCBTARANIS) && defined(BLUETOOTH)