Flash/ROM area that are not erased at a flash erase.

[Christian Egnér]

I'm creating a system test for manufactured units and if it's OK I would like to set a permanent flag in an area that
will not be erased if I erase flash at a firmware update. Are there any such memory areas I can use?

[Syed Maysum Abbas Zaidi]

Hi,

On nRF52840, a normal firmware update (DFU) erases the application flash. So If you need to store a permanent flag that is not erased when flash is erased during a firmware update, the recommended solution is to store it in UICR (User Information Configuration Registers). UICR is not affected by firmware updates (DFU).

Best Regards,
Syed Maysum