diff --git a/radio/src/hal/adc_driver.cpp b/radio/src/hal/adc_driver.cpp
index 19a14c18f..b68c04bef 100644
--- a/radio/src/hal/adc_driver.cpp
+++ b/radio/src/hal/adc_driver.cpp
@@ -76,13 +76,15 @@ const etx_hal_adc_driver_t* etx_hal_adc_driver = nullptr;
                                              0 /*TX_VOLTAGE*/, 0 /*TX_VBAT*/,
                                              0 /*SWB*/, 0 /*SWD*/};
 
+#elif defined(PCBX12S)
+  const int8_t adcDirection[NUM_ANALOGS] = {1,-1,1,-1,  -1,1,-1,  -1,-1,  -1,1, 0,0,0};
 #else
   #error "ADC driver does not suppport this target"
 #endif
 
 uint16_t adcValues[NUM_ANALOGS] __DMA;
 
-#if defined(PCBX10)
+#if defined(PCBX10) || defined(PCBX12S)
 uint16_t rtcBatteryVoltage;
 #endif
 
@@ -117,7 +119,9 @@ static bool adcSingleRead()
   return true;
 }
 
-bool adcRead() __attribute__((weak))
+// Declare adcRead() weak so it can be re-declared
+#pragma weak adcRead
+bool adcRead()
 {
   uint16_t temp[NUM_ANALOGS] = { 0 };
 
@@ -151,7 +155,7 @@ uint16_t getRTCBatteryVoltage()
 {
 #if defined(HAS_TX_RTC_VOLTAGE)
   return (getAnalogValue(TX_RTC_VOLTAGE) * ADC_VREF_PREC2) / 2048;
-#elif defined(PCBX10)
+#elif defined(PCBX10) || defined(PCBX12S)
   return (rtcBatteryVoltage * 2 * ADC_VREF_PREC2) / 2048;
 #elif defined(PCBNV14)
   #warning "TODO RTC voltage"
diff --git a/radio/src/hal/adc_driver.h b/radio/src/hal/adc_driver.h
index 3f7f02642..d9256ef62 100644
--- a/radio/src/hal/adc_driver.h
+++ b/radio/src/hal/adc_driver.h
@@ -41,7 +41,7 @@
 #endif
 
 // TODO: get rid of this special case
-#if defined(PCBX10)
+#if defined(PCBX10) || defined(PCBX12S)
 extern uint16_t rtcBatteryVoltage;
 #endif
 
@@ -54,8 +54,6 @@ struct etx_hal_adc_driver_t {
 bool adcInit(const etx_hal_adc_driver_t* driver);
 // void adcDeInit();
 
-// Declare adcRead() weak so it can be re-declared
-bool adcRead() __attribute__((weak));
-
+bool     adcRead();
 uint16_t getRTCBatteryVoltage();
 uint16_t getAnalogValue(uint8_t index);
diff --git a/radio/src/targets/horus/CMakeLists.txt b/radio/src/targets/horus/CMakeLists.txt
index 1ff3ea877..2c71792a1 100644
--- a/radio/src/targets/horus/CMakeLists.txt
+++ b/radio/src/targets/horus/CMakeLists.txt
@@ -138,6 +138,7 @@ elseif (PCB STREQUAL X12S)
     )
   set(FIRMWARE_TARGET_SRC
     ${FIRMWARE_TARGET_SRC}
+    ../../hal/adc_driver.cpp
     x12s_adc_driver.cpp
     )
   set(BITMAPS_TARGET x12s_bitmaps)
diff --git a/radio/src/targets/horus/board.cpp b/radio/src/targets/horus/board.cpp
index b215f753d..4faa08b93 100644
--- a/radio/src/targets/horus/board.cpp
+++ b/radio/src/targets/horus/board.cpp
@@ -26,7 +26,7 @@
   #include "../common/arm/stm32/stm32_hal_adc.h"
   #define ADC_DRIVER stm32_hal_adc_driver
 #else
-  #include "x12_adc_driver.h"
+  #include "x12s_adc_driver.h"
   #define ADC_DRIVER x12s_adc_driver
 #endif
 
diff --git a/radio/src/targets/horus/x12s_adc_driver.cpp b/radio/src/targets/horus/x12s_adc_driver.cpp
index e4628cd96..737cc52d7 100644
--- a/radio/src/targets/horus/x12s_adc_driver.cpp
+++ b/radio/src/targets/horus/x12s_adc_driver.cpp
@@ -19,9 +19,8 @@
  */
 
 #include "opentx.h"
+#include "x12s_adc_driver.h"
 
-uint16_t adcValues[NUM_ANALOGS] __DMA;
-uint16_t rtcBatteryVoltage;
 
 #define ADC_CS_HIGH()                  (ADC_SPI_GPIO->BSRRL = ADC_SPI_PIN_CS)
 #define ADC_CS_LOW()                   (ADC_SPI_GPIO->BSRRH = ADC_SPI_PIN_CS)
@@ -137,11 +136,8 @@ static bool x12s_adc_init()
   ADC1->SQR3 = (ADC_Channel_Vbat << 0);
   ADC1->SMPR1 = (ADC_SAMPTIME << 0) + (ADC_SAMPTIME << 3) + (ADC_SAMPTIME << 6) + (ADC_SAMPTIME << 9) + (ADC_SAMPTIME << 12) + (ADC_SAMPTIME << 15) + (ADC_SAMPTIME << 18) + (ADC_SAMPTIME << 21) + (ADC_SAMPTIME << 24);
   ADC1->SMPR2 = (ADC_SAMPTIME << 0) + (ADC_SAMPTIME << 3) + (ADC_SAMPTIME << 6) + (ADC_SAMPTIME << 9) + (ADC_SAMPTIME << 12) + (ADC_SAMPTIME << 15) + (ADC_SAMPTIME << 18) + (ADC_SAMPTIME << 21) + (ADC_SAMPTIME << 24) + (ADC_SAMPTIME << 27);
-}
 
-uint16_t getRTCBatteryVoltage()
-{
-  return (rtcBatteryVoltage * 2 * ADC_VREF_PREC2) / 2048;
+  return true;
 }
 
 const uint16_t adcCommands[MOUSE1+2] =
@@ -229,7 +225,7 @@ bool adcOnChipReadFinished()
 
 // Re-declare adcRead()
 // (takes precedence over hal/adc_driver.cpp)
-void adcRead()
+bool adcRead()
 {
   uint16_t temp[NUM_ANALOGS-MOUSE1] = { 0 };
   uint8_t noInternalReads = 0;
@@ -268,19 +264,9 @@ void adcRead()
   if (isVBatBridgeEnabled()) {
     rtcBatteryVoltage = ADC1->DR;
   }
-}
 
-#if !defined(SIMU)
-const int8_t ana_direction[NUM_ANALOGS] = {1,-1,1,-1,  -1,1,-1,  -1,-1,  -1,1, 0,0,0};
-
-uint16_t getAnalogValue(uint8_t index)
-{
-  if (ana_direction[index] < 0)
-    return 4095 - adcValues[index];
-  else
-    return adcValues[index];
+  return true;
 }
-#endif // #if !defined(SIMU)
 
 //TODO: implement these based on stm32_hal_adc.cpp
 //static bool x12s_adc_init();