RE: Erase protect and App protect in nRF5340

Maria Gilje — Mon, 20 Apr 2026 13:30:55 GMT

Hello,

Do you have any firmware on one or both of the cores on your nRF5340 which sets the ERASEPROTECT.DISABLE register to a non-zero 32-bit key value? If you don't have that and ERASEPROTECT and APPROTECT is enabled for both cores, we no NOT have a recovery method from this point.

If you do have a key written to CTRL-APs ERASEPROTECT.DISABLE register in your firmware, you can disable erase protection by writing the same key to the debugger side ERASEPROTECT.DISABLE register. The base addresses can be found here for the application (ns + s) and network cores. Also available in the linked documentation are instructions on how to disable AP protection and erase protection.

Going forward, I advise you to read back the ERASEPROTECT.STATUS before enabling APPROTECT for your device(s). You should not enable APPROTECT and ERASEPROTECT at the same time unless you have firmware which sets the *.DISABLE register(s) to a 32-bit key and you can use that same key by following the instructions for diabling erase and access port protection.

Best regards,

Maria