Read back protection on nRF52840 old and new build codes/hardware revisions

RE: Read back protection on nRF52840 old and new build codes/hardware revisions

user75734 — Wed, 09 Feb 2022 09:19:10 GMT

According to the nrf52840_bitfields.h you can force enable the APPROTECT by setting APPROTECT_FORCEPROTECT_FORCEPROTECT_Force.

ENABLE_APPROTECT can be set in the CMakeLists.txt of your project.

Best regards,

Simon

RE: Read back protection on nRF52840 old and new build codes/hardware revisions

user86629 — Tue, 08 Feb 2022 16:56:24 GMT

Hi,

Thanks for your reply. I am using Zephyr v2.7.0. I hope this helps you to answer my questions.

If I got it right, then the only thing I need to do for newer hardware versions (Fxx and later) is to add to my code above (that already writes 0xFFFFFF00 to UICR->APPROTECT and does a cold reset) the following step:

--> "write APPROTECT.FORCEPROTECT to Force (0x00)" after the mcu reboots.

Could you please confirm my understanding?

Is there a Zephyr Conf "ENABLE_APPROTECT" that I need to do? As I said, for the device of build code "AAD0", the code above works without problems.

RE: Read back protection on nRF52840 old and new build codes/hardware revisions

user75734 — Tue, 08 Feb 2022 13:48:56 GMT

What version of the nRFConnect SDK or Zephyr are you using? Due to the changes in the MDK there is a requirement to use firmware based on nRFConnect SDK v1.6.0 (Zephyr v2.6.0) or later. You can see IN-141 for more information.

Best regards,

Simon