Try some code from ST_NUCLEO32_F042K6

keyboards/simontester/boards/GENERIC_STM32_F04/board.c

@@ -29,14 +29,12 @@ const PALConfig pal_default_config = {
 #endif
 #if STM32_HAS_GPIOB
   {VAL_GPIOB_MODER, VAL_GPIOB_OTYPER, VAL_GPIOB_OSPEEDR, VAL_GPIOB_PUPDR,
-   VAL_GPIOB_ODR,   VAL_GPIOB_AFRL},
+   VAL_GPIOB_ODR,   VAL_GPIOB_AFRL,   VAL_GPIOB_AFRH},
 #endif
-/*
 #if STM32_HAS_GPIOC
   {VAL_GPIOC_MODER, VAL_GPIOC_OTYPER, VAL_GPIOC_OSPEEDR, VAL_GPIOC_PUPDR,
    VAL_GPIOC_ODR,   VAL_GPIOC_AFRL,   VAL_GPIOC_AFRH},
 #endif
-*/
 #if STM32_HAS_GPIOD
   {VAL_GPIOD_MODER, VAL_GPIOD_OTYPER, VAL_GPIOD_OSPEEDR, VAL_GPIOD_PUPDR,
    VAL_GPIOD_ODR,   VAL_GPIOD_AFRL,   VAL_GPIOD_AFRH},
@@ -47,7 +45,7 @@ const PALConfig pal_default_config = {
 #endif
 #if STM32_HAS_GPIOF
   {VAL_GPIOF_MODER, VAL_GPIOF_OTYPER, VAL_GPIOF_OSPEEDR, VAL_GPIOF_PUPDR,
-   VAL_GPIOF_ODR,   VAL_GPIOF_AFRL},
+   VAL_GPIOF_ODR,   VAL_GPIOF_AFRL,   VAL_GPIOF_AFRH},
 #endif
 #if STM32_HAS_GPIOG
   {VAL_GPIOG_MODER, VAL_GPIOG_OTYPER, VAL_GPIOG_OSPEEDR, VAL_GPIOG_PUPDR,