boot: bootutil: swap_scratch: Fix issue with bricking device (f76fba70) · Commits · Wenxi XU / Mcuboot

Fixes an issue with the swap using scratch algorithm that would cause the image loaded into the primary slot to be corrupt and unbootable if a device was rebooted during an erase of the scratch section that had not completed Signed-off-by:

Jamie McCrae <jamie.mccrae@nordicsemi.no>

boot/bootutil/src/swap_scratch.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -778,7 +778,12 @@ boot_swap_sectors(int idx, uint32_t sz, struct boot_loader_state *state,
		BOOT_STATUS_ASSERT(rc == 0);

		if (erase_scratch) {
		rc = boot_erase_region(fap_scratch, 0, flash_area_get_size(fap_scratch), false);
		/* Scratch trailers MUST be erased backwards, this is to avoid an issue whereby a
		* device reboots in the process of erasing the scratch if it erased forwards, if that
		* happens then the scratch which is partially erased would be wrote back to the
		* primary slot, causing a corrupt unbootable image
		*/
		rc = boot_erase_region(fap_scratch, 0, flash_area_get_size(fap_scratch), true);
		assert(rc == 0);
		}
		}

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