RE: nRF54L10 - make MCUboot immutable

Amanda Hsieh — Mon, 20 Apr 2026 14:11:12 GMT

No.

RE: nRF54L10 - make MCUboot immutable

pawpec — Mon, 20 Apr 2026 08:36:41 GMT

Thank you Amanda for detailed response!

OK so can I use MPC (https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/mpc.html) then to make >62 kB MCUboot to be fully immutable?

RE: nRF54L10 - make MCUboot immutable

Amanda Hsieh — Fri, 17 Apr 2026 19:23:03 GMT

Hi,

[quote user=""]I've read that there's FPROTECT mechanism (Fail to boot after upgrade to NCS 3.1.1 , https://docs.nordicsemi.com/bundle/ncs-3.1.0/page/nrf/app_dev/device_guides/nrf54l/dfu_config.html) but it seems that's only for first 62 kB of RRAM when CONFIG_FPROTECT_ALLOW_COMBINED_REGIONS is used. [/quote]

That's correct.

[quote user=""] Is that setting permanent once it's activated?[/quote]

It can be removed with a chip erase (ERASEALL), unless erase protection is enabled.

[quote user=""]Does this part of datasheet refers to FPROTECT mechanism (and is it actually 62 kB combined, not 64 kB since RW1 is 5bit (32)))?[/quote]

The SIZE field in UICR.BOOTCONF (field G) is a 5-bit field, giving a maximum of 31 kB per the register layout shown.

[quote user=""]Is there ANY other mechanism to protect 126 kB MCUBoot partition against writes on nRF54L10 which I've missed?[/quote]

Unfortunately, no. See the CONFIG_FPROTECT_ALLOW_COMBINED_REGIONS config description.

Regards,
Amanda H.