I've been closely following AN12283 and the chip reference manual. I am trying to evaluate secure boot on my LPCXpresso55S69.
I made the mistake of enabling secure boot through the boot ROM before programming a signed image. I used "elftosb-gui" in the 2.7.1 SDK to set secure boot to boot signed images, and then I reset the chip.
Now I can no longer program any flash from the boot rom, or I get "Command disallowed when security is enabled".
I can still access the device and program flash using my JLINK debugger, but it is unable to execute any of the code. I tried programming a signed application with the JLINK, but to no success.
I can see the CMPA page through JLINK/GDB, and I see SECURE_BOOT_CFG == 0x40000000, meaning secure boot is indeed enabled. I have tried numerous times to set SECURE_BOOT_CFG back to 0 using GDB, but none of my writes to CMPA work. Seems CMPA is immutable.
I did not seal any configuration with a sha256 hash, so I was under the impression I could roll back any changes but I haven't figured out how.
Is there anyway I can turn off secure boot and try again? How?
