Device Recovery

Unable to program

Locked core

When using probe-rs you may run into an issue like this one:

probe-rs download –chip nRF9151_xxAA –binary-format hex build_feather_nrf9151_ns/merged.hex –allow-erase-all
WARN probe_rs::vendor::nordicsemi::sequences::nrf: Core 0 is locked. Erase procedure will be started to unlock it.
WARN probe_rs::architecture::arm::core::armv8m: The core is in locked up status as a result of an unrecoverable exception
Erasing ✔ 100% [####################] 424.00 KiB @ 38.40 KiB/s (took 11s)
Programming ✔ 100% [####################] 424.00 KiB @ 38.78 KiB/s (took 11s) Finished in 21.98s

Any error that refers to a locked core, indicates the device is in a bad state.

Connecting to the chip was unsuccessful

If you interrupt a programming session in progress, the UICR on the 9151 may find its way into a unsupported state. This results in the following error:

Executing task: probe-rs download --chip nRF9151_xxAA --binary-format hex build/circuitdojo_feather_nrf9151/merged.ed.hex --probe 2e8a:000c:E66382593669B21

Error: Connecting to the chip was unsuccessful.

Caused by:
0: An ARM specific error occurred.
1: Error using access port FullyQualifiedApAddress { dp: Default, ap: V1(0) }.
2: Failed to read register DRW at address 0x0c
3: An error occurred in the communication with an access port or debug port.
4: Target device responded with a FAULT response to the request.

The terminal process "/opt/homebrew/bin/zsh '-l', '-c', 'probe-rs download --chip nRF9151_xxAA --binary-format hex build/circuitdojo_feather_nrf9151/merged.ed.hex --

The Solution

Make sure you have the rust toolchain installed before you get to the next step.

Download the recovery utility and run it with the hex you'd like to program:

git clone https://github.com/circuitdojo/recovery.git
cd recovery
cargo install --path .
recovery path/to/your/merged.hex

More information can be found here: https://github.com/circuitdojo/recovery

Device no longer shows up on your machine

In rare cases the RP2040 firmware may become corrupted. The easiest way to restore it is by following this proceedure:

  1. Unplug your 9151 Feather
  2. While pressing the BS button plug in the USB cable and count "1 Mississippi"

Board button

  1. Wait for your computer to initialize as a disk drive.

Bootloader disk

  1. Download the latest debugprobe.uf2 from Github here: https://github.com/raspberrypi/debugprobe/releases. Copy it from the app/_hex/ folder to the newly appeared disk drive.

  2. The RP2040 should restart and initialize immediately. If you're on Linux you can run lsusb to see if it's setup correctly:

lsusb output