MCUBoot erases flash area defined as "custom"

RE: MCUBoot erases flash area defined as "custom"

Sigurd Hellesvik — Mon, 17 Jun 2024 14:33:02 GMT

[quote user="Albert_0"]- Both mcuboot areas need to have the same size apparently, otherwise the "new" firmware gets stuck in the "pending" state and it's impossible to get it out of there.[/quote]

Yep, this is very important. Changing partition size can cause undefined behaviour.

[quote user="Albert_0"]- For the new memory layout to take effect and work, the whole flash needs to be erased, otherwise we get the same issues as before.[/quote]

Yes, meaning that you cannot fix partitioning in DFU (with only one bootloader)

And a third point:

- There is a known issue (working to get it on the list), that you cannot use more than 95% of available application space, because MCUboot uses the last ~5% of mcuboo_secondary for stuff

Bonus tip:

[quote user="Albert_0"]For reference, the new layout is:[/quote]

You can use VS Code -> Memory Layout -> Parititons to view a nice version of the layout.
Or if your prefer the CLI. "west build -t partition_manager_report"

RE: MCUBoot erases flash area defined as "custom"

Albert_0 — Mon, 17 Jun 2024 13:46:54 GMT

Hi Sigurd, thanks for the response.

After writing the question and changing the memory areas removing the overlap now it all works without having to go into the advanced settings.

Two things I noticed (also based on other posts, from other users)

- Both mcuboot areas need to have the same size apparently, otherwise the "new" firmware gets stuck in the "pending" state and it's impossible to get it out of there.

- For the new memory layout to take effect and work, the whole flash needs to be erased, otherwise we get the same issues as before.

For reference, the new layout is:

mcuboot: 0x0 -> 0xC000
mcuboot_pad: 0xC000 -> 0xC200
app: 0xC200 -> 0x84000
mcuboot_primary: 0xC000 -> 0x84000
empty_0: 0x84000 -> 0x85000
custom: 0x85000 -> 0x86000
mcuboot_primary_app: 0xC200 -> 0x84000
mcu_boot_secondary: 0x86000 -> 0xFE000
empty_1: 0xFE000 -> 0x100000

Cheers,

Alberto

RE: MCUBoot erases flash area defined as "custom"

Sigurd Hellesvik — Mon, 17 Jun 2024 11:15:41 GMT

Hi,

This is a "feature" in the nRF Device Manager app.
Go to "advanced" settings and unselect the "delete storage" when doing OTA.

Does that fix the issue?

That being said, if any of the mcuboot partitions overlay your empty partition, they may at any time overwrite it, so I recommend not having overlap

Regards,
Sigurd Hellesvik