diff --git a/hw/arm/prusa/stm32f407/stm32f4xx_adc.c b/hw/arm/prusa/stm32f407/stm32f4xx_adc.c
index aacf40165b..b5669a08d0 100644
--- a/hw/arm/prusa/stm32f407/stm32f4xx_adc.c
+++ b/hw/arm/prusa/stm32f407/stm32f4xx_adc.c
@@ -77,7 +77,7 @@ enum RegIndex {
 
 typedef struct STM32F4XXADCCState STM32F4XXADCCState;
 
-#define ADC_NUM_REG_CHANNELS 16
+#define ADC_NUM_REG_CHANNELS 18
 
 OBJECT_DECLARE_SIMPLE_TYPE(STM32F4XXADCState, STM32F4xx_ADC)