diff --git a/radio/src/targets/common_avr/adc_driver.cpp b/radio/src/targets/common_avr/adc_driver.cpp
index d92da7511..9c859702e 100644
--- a/radio/src/targets/common_avr/adc_driver.cpp
+++ b/radio/src/targets/common_avr/adc_driver.cpp
@@ -49,9 +49,10 @@ void adcInit()
 
 void adcPrepareBandgap()
 {
+#if defined(CPUM2560) && !defined(PCBMEGA2560)  
+   ADCSRB &= ~(1<<MUX5); // For PCB V4, use our own 1.2V, external reference (connected to ADC3)
+#endif
 #if defined(CPUM2560)
-  // For PCB V4, use our own 1.2V, external reference (connected to ADC3)
-  ADCSRB &= ~(1<<MUX5);
   ADMUX = 0x03|ADC_VREF_TYPE; // Switch MUX to internal reference
 #else
   ADMUX = 0x1E|ADC_VREF_TYPE; // Switch MUX to internal reference