https://devzone.nordicsemi.com/f/nordic-q-a/77559/boot-making-itself-immutableMy understanding is that secure boot calls an interface to make portion flash that contains a bootloader immutable. Since this is called after the bootloader start to run, does it mean there is no immutability before this instruction? Is that not aen-USTelligent Community 13Tue, 20 Jul 2021 12:22:57 GMThttps://devzone.nordicsemi.com/thread/320886?ContentTypeID=1Tue, 20 Jul 2021 12:22:57 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a0fa84f0-a83c-4cc7-8590-553bf9ff6b52Simon<p>The immutable bootloader will lock itself&nbsp;in the start&nbsp;</p> <div><a title="https://github.com/nrfconnect/sdk-nrf/blob/799d96f2802b648d9c0d62e8b62bf4703354cafe/samples/bootloader/src/main.c#l72" href="https://github.com/nrfconnect/sdk-nrf/blob/799d96f2802b648d9c0d62e8b62bf4703354cafe/samples/bootloader/src/main.c#L72" rel="noopener noreferrer" target="_blank">i_https://github.com/nrfconnect/sdk-nrf/blob/799d96f2802b648d9c0d62e8b62bf4703354cafe/samples/bootloader/src/main.c#L72.</a></div> <div></div> <div>Since this is done immediately, there is no possible way to run an attack before this. So this solution poses no security issues.</div> <div></div> <div>Best regards,</div> <div>Simon</div><div style="clear:both;"></div>