STM32H743 Flash erase erases the wrong bank

Hi,

I am building a program that can flash new firmware onto a STM32H743ZIT6 via CAN. It does so by utilizing the dual bank feature and ping-ponging between bank 1 and bank 2. It receives the firmware via CAN and buffers it. Before writing it to the inactive bank it first erases said bank.

When running form bank 1 this works just fine and it is able to reboot to the newly flashed bank. When going from bank 2 back to bank 1 however, it encounters an issue. It crashes in the erase step and will not restart.

After I manually disable the SWAP_BANK bit using STM32CubeProgrammer it runs again on bank 1 without flashing again. This (I think) tells me it is deleting bank 2 while also running on it.

Attached you find the function in question, do you have any idea where i went wrong?

void foc_erase_inactive_bank() {
 // Determine inactive bank from SWAP_BANK bit
 uint8_t inactive_bank = (FLASH->OPTCR & FLASH_OPTCR_SWAP_BANK) ? 1 : 2;
 uint32_t bank_to_erase = (inactive_bank == 1) ? FLASH_BANK_1 : FLASH_BANK_2;

 LOG_INFO("FOC [ERASE] Starting mass erase of bank %u", inactive_bank);

 // unlock flash
 if (HAL_FLASH_Unlock() != HAL_OK) {
 LOG_ERROR("FOC [ERASE] HAL_FLASH_Unlock failed");
 foc.state = FOC_STATE_ERROR;
 return;
 }
 // Disable instruction cache prior to flash operation
 SCB_DisableICache();

 // Configure and execute mass erase
 FLASH_EraseInitTypeDef erase_init = {
 .TypeErase = FLASH_TYPEERASE_MASSERASE,
 .Banks = bank_to_erase,
 .VoltageRange = FLASH_VOLTAGE_RANGE_3,
 };

 uint32_t erase_error = 0U;
 HAL_StatusTypeDef erase_result = HAL_FLASHEx_Erase(&erase_init, &erase_error);

 // Re-enable cache and lock flash
 SCB_EnableICache();
 HAL_FLASH_Lock();

 // handle error
 if (erase_result != HAL_OK) {
 uint32_t hal_error = HAL_FLASH_GetError();
 LOG_ERROR(
 "FOC [ERASE] Mass erase failed with status %lu, HAL error: 0x%08X",
 (unsigned long)erase_result, hal_error);
 foc.state = FOC_STATE_ERROR;
 return;
 }

 LOG_INFO("FOC [ERASE] Successfully erased bank %u", inactive_bank);
}