docs: factory reset

Add instructions to recover broken thingy91x devices.

Signed-off-by: Maximilian Deubel <[email protected]>

Author: maxd-nordic

docs/links.txt

@@ -13,7 +13,8 @@
 .. _`Cellular Monitor app`: https://docs.nordicsemi.com/bundle/nrf-connect-cellularmonitor/page/index.html
 .. _`Serial Terminal app`: https://docs.nordicsemi.com/bundle/nrf-connect-serial-terminal/page/index.html
 .. _`Getting started guide`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/installation.html
-.. _`nRF Util`: https://docs.nordicsemi.com/bundle/nrf-connect-serial-terminal/page/index.html
+.. _`nRF Util`: https://docs.nordicsemi.com/bundle/nrfutil/page/README.html
+.. _`Installing nRF Util`: https://docs.nordicsemi.com/bundle/nrfutil/page/guides/installing.html
 .. _`Connectivity Bridge`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/applications/connectivity_bridge/README.html
 
 .. ### github.com
@@ -32,6 +33,12 @@
 
 .. _`Interactive BOM PCA20065 1.0.0.`: https://htmlpreview.github.io/?https://github.com/hello-nrfcloud/firmware/blob/main/docs/pca20065_1_0_0.html
 
+.. _`nRF5340 application firmware`: https://github.com/hello-nrfcloud/firmware/releases/download/v2.0.1/connectivity-bridge-v2.0.1-thingy91x-nrf53-app.hex
+.. _`nRF5340 network firmware`: https://github.com/hello-nrfcloud/firmware/releases/download/v2.0.1/connectivity-bridge-v2.0.1-thingy91x-nrf53-net.hex
+.. _`nRF9151 firmware`: https://github.com/hello-nrfcloud/firmware/releases/download/v2.0.1/hello.nrfcloud.com-v2.0.1+debug-thingy91x-nrf91.hex
+.. _`nRF5340 DFU`: https://github.com/hello-nrfcloud/firmware/releases/download/v2.0.1/connectivity-bridge-v2.0.1-thingy91x-nrf53-dfu.zip
+.. _`nRF9151 DFU`: https://github.com/hello-nrfcloud/firmware/releases/download/v2.0.1/hello.nrfcloud.com-v2.0.1+debug-thingy91x-nrf91-dfu.zip
+
 .. _`pyOCD`: https://github.com/pyocd/pyOCD
 
 .. _`hello.nrfcloud.com`: https://hello.nrfcloud.com/

docs/troubleshooting.rst

@@ -40,3 +40,84 @@ Complete the following steps to capture and dump modem traces:
           modem_trace stop         # Stop modem tracing if running
           modem_trace size         # Check the size of stored traces
           modem_trace dump_uart    # Dump traces to UART 1 for analysis
+
+Factory reset (Bootloader)
+**************************
+
+If you have not used a debug probe to program your Thingy:91 X, and it became unresponsive, it is possible to recover the device without additional tools.
+
+See `Installing nRF Util`_ for instructions for installing nRF Util. Install the nRF Util device command as well.
+Download the following files from the hello-nrfcloud/firmware release:
+
+* `nRF5340 DFU`_
+* `nRF9151 DFU`_
+
+If the device shows up on USB, the nRF5340 is correctly running the Connectivity bridge.
+If not, you can try to put the nRF5340 into serial recovery mode.
+This is done by turning off the device using the power switch, and pressing and holding **Button 2** while turning it back on.
+An MCUboot device shows up.
+
+.. code-block:: none
+
+   nrfutil device program --firmware connectivity-bridge-v2.0.1-thingy91x-nrf53-dfu.zip --traits mcuboot
+
+Then, the Connectivity bridge triggers serial recovery mode for the nRF9151 automatically.
+
+Alternatively, you can force the nRF9151 serial recovery mode the same way with the nRF5340, but using **Button 1** instead.
+
+.. code-block:: none
+
+   nrfutil device program --firmware hello.nrfcloud.com-v2.0.1-thingy91x-nrf91-dfu.zip --traits mcuboot
+
+Factory reset (J-Link)
+**********************
+
+If your Thingy:91 X is powered on and connected using a USB cable, it shows up as a USB device.
+Else, something is preventing the Connectivity bridge application on the nRF5340 from running.
+For example, this could be an application running on the nRF9151 that is driving the wrong pins.
+Another typical case is that the nRF5340 has been flashed by accident.
+
+You need to use an external J-Link to follow these steps.
+A Nordic development kit with a debug-out port can be used as well.
+
+See `Installing nRF Util`_ for instructions for installing nRF Util. Install the nRF Util device command as well.
+Download the following files from the hello-nrfcloud/firmware release:
+
+* `nRF5340 application firmware`_
+* `nRF5340 network firmware`_
+* `nRF9151 firmware`_
+
+Set the SWD switch to **nRF91** and run the ``nrfutil device recover`` command to recover the nRF9151.
+Repeat the same for the nRF5340. You can use the ``nrfutil device device-info`` command to check that you are connected to the correct chip.
+When using a DK, there is an ambiguity between targeting the on-board chip and using debug-out.
+Running the ``nrfutil device device-info`` command is recommended to make sure you are not programming the on-board target accidentally.
+
+If nRF5340 recovery fails, an nRF9151 firmware might have been flashed previously.
+Even though the device shows up as unrecoverable, the soft-lock can be removed with these commands.
+You might have to repeat them for a successful result.
+Do not use them on an nRF91 Series device.
+
+.. code-block:: none
+
+   nrfutil device recover --x-family nrf53 --core Network --traits jlink
+   nrfutil device recover --x-family nrf53 --core Application --traits jlink
+
+Now that both chips are recovered, set the SWD switch to **nRF91**.
+To check you are connected to the correct chip, run the ``nrfutil device device-info`` command.
+
+.. code-block:: none
+
+   nrfutil device program --firmware hello.nrfcloud.com-v2.0.1+debug-thingy91x-nrf91.hex
+
+Set the SWD switch to **nRF53**.
+To check you are connected to the correct chip, run the ``nrfutil device device-info`` command.
+
+.. code-block:: none
+
+   nrfutil device program --core Network --options reset=RESET_NONE,chip_erase_mode=ERASE_ALL,verify=VERIFY_NONE --firmware connectivity-bridge-v2.0.1-thingy91x-nrf53-net.hex
+   nrfutil device program --options reset=RESET_SYSTEM,chip_erase_mode=ERASE_ALL,verify=VERIFY_NONE --firmware connectivity-bridge-v2.0.1-thingy91x-nrf53-app.hex
+
+The device shows up as a USB device again.
+Press **Button 2** to reset the nRF9151 DK.
+If you see that **LED 1** lights up, the recovery was successful.
+If you do not have a usable device after this procedure, contact Nordic Semiconductor's technical support on `DevZone`_.