trezor-firmware/bootloader/usb_erase.h

static void erase_storage_code_progress(void)
{
	flash_wait_for_last_operation();
	flash_clear_status_flags();
	flash_unlock();
	// erase storage area
	for (int i = FLASH_STORAGE_SECTOR_FIRST; i <= FLASH_STORAGE_SECTOR_LAST; i++) {
		layoutProgress("WIPING ... Please wait", 1000 * (i - FLASH_STORAGE_SECTOR_FIRST) / (FLASH_CODE_SECTOR_LAST - FLASH_STORAGE_SECTOR_FIRST));
		flash_erase_sector(i, FLASH_CR_PROGRAM_X32);
	}
	// erase code area
	for (int i = FLASH_CODE_SECTOR_FIRST; i <= FLASH_CODE_SECTOR_LAST; i++) {
		layoutProgress("WIPING ... Please wait", 1000 * (i - FLASH_STORAGE_SECTOR_FIRST) / (FLASH_CODE_SECTOR_LAST - FLASH_STORAGE_SECTOR_FIRST));
		flash_erase_sector(i, FLASH_CR_PROGRAM_X32);
	}
	flash_wait_for_last_operation();
	flash_lock();
}

static void erase_code_progress(void)
{
	flash_wait_for_last_operation();
	flash_clear_status_flags();
	flash_unlock();
	for (int i = FLASH_CODE_SECTOR_FIRST; i <= FLASH_CODE_SECTOR_LAST; i++) {
		layoutProgress("PREPARING ... Please wait", 1000 * (i - FLASH_CODE_SECTOR_FIRST) / (FLASH_CODE_SECTOR_LAST - FLASH_CODE_SECTOR_FIRST));
		flash_erase_sector(i, FLASH_CR_PROGRAM_X32);
	}
	layoutProgress("INSTALLING ... Please wait", 0);
	flash_wait_for_last_operation();
	flash_lock();
}

static void erase_storage(void)
{
	flash_wait_for_last_operation();
	flash_clear_status_flags();
	flash_unlock();
	for (int i = FLASH_STORAGE_SECTOR_FIRST; i <= FLASH_STORAGE_SECTOR_LAST; i++) {
		flash_erase_sector(i, FLASH_CR_PROGRAM_X32);
	}
	flash_wait_for_last_operation();
	flash_lock();
}