RE: Device protection

sellapio — Tue, 26 Aug 2025 04:24:25 GMT

[deleted]

johnnagardner — Fri, 25 Aug 2023 09:53:30 GMT

Hello,

To remove the protection and successfully flash the NRF Bootloader via OpenOCD, you need to follow these steps:

1. Disable the UICR APPROTECT:

Locate the UICR (User Information Configuration Registers) section in your code or configuration files.
Find the entry related to "APPROTECT" or "UICR->APPROTECT" and set its value to 0 or disable it.

2.Save the changes and rebuild your code or configuration files to ensure the updated settings are applied.

3. Connect a low-level adapter:

Since a high-level adapter like the ST-Link cannot access the CTRL-AP (Control Access Port) required for device recovery, you need to use a low-level adapter that supports it. Examples of such adapters include J-Link and Segger.
Connect the low-level adapter to your NRF52 device, ensuring proper connections and compatibility.

4. Use the 'nrf52_recover' command:

With the low-level adapter successfully connected, you can now use the 'nrf52_recover' command to remove the protection and recover the device from AP lock.
Execute the command via the OpenOCD command line or the relevant interface specific to your adapter.

Håkon Alseth — Wed, 29 Mar 2023 11:31:45 GMT

Hi,

If openocd does not have updated functionality on performing a recovery, I would recommend that you obtain a JLink debugger.

If you have a nRF5-series DK, you can use this kit as a debugger/programmer for external boards.

Kind regards,

Håkon