Rescue Firmware Version 2x

There have been reports that new My Cloud (PR4100, EX2 Ultra, etc) devices may be shipping with rescue (Safe Mode) firmware version, that could potentially cause the devices to be “bricked” under certain circumstances.

The rescue firmware version can be checked using the rescue_fw -c command via an SSH connection, which works on OS5 or OS3, and makes no changes to the device.

# rescue_fw -c
Rescue FW version:
Rescue fw checksum(fw):a787077b
Verify Rescue FW Succeded

If the rescue firmware of your device is version or above, can you please use the following commands to extract the rescue firmware, then upload it somewhere so I can examine it? Be sure to change the output path if required. The following commands do NOT pertain to My Cloud DL series, single bay, or MCH (Home) devices.

My Cloud PR Series Devices (PR4100, PR2100, etc):

  • mkdir /tmp/wdnas_rescue_fw
  • mount /dev/mmcblk0p5 /tmp/wdnas_rescue_fw
  • cp /tmp/wdnas_rescue_fw/rescue_firmware /shares/Public/rescue_fw_20_mmcblk0p5.bin

My Cloud EX Series Devices (EX2 Ultra, EX4100, etc):

  • nanddump /dev/mtd4 -f /shares/Public/rescue_fw_20_mtd4.bin

Also, if the rescue firmware of your device is version or above, please provide the serial number (minus the last 4 digits) so I can decode it to learn when the devices were made, thus narrowing down the date range of when the rescue firmware may have been modified.

Example: WNAN3150xxxx


I had EX2 Ultra with OS/5 (FW V5.08.xx) loaded and running.
Device was 14 months old, and originally had OS/3 loaded.

I did a reversion back to OS/3 this morning.

As recommended, I erased the Kernel and Config files.
I rebooted and device booted to Rescue firmware as expected.
FW for the rescue firmware was
Reversion went fine (and quick)

I imagine if I had a rescue firmware (if that actually exists), the right answer would have been to load an OS/5 firmware.