D455 'Device Enumeration Failed' after rolling back firmware

We have a serious issue with the last two orders of Intel Realsense D455 sensors.

There is at least one firmware version that, when rolled back to the firmware version our software supports, bricks and will not enumerate in Windows any longer.

The firmware version I have reproduced the issue with is 05.13.00.55.  When we attempt to update firmware to version 05.12.07.100, the update completes successfully without errors, and the sensor disconnects. After a timeout period, the firmware updater reports an error that the sensor did not reconnect after an allotted period of time. The sensor then cannot be detected properly by Windows.

After this update, the sensor appears in the device manager as a generic USB device with error "invalid configuration descriptor". Realsense Viewer, SDK, fw-update tool all cannot find a Realsense device attached.

I have 18 new customers so far who have encountered this issue, and I have reproed this on several sensors myself while testing. I am now pulling our entire stock of sensors to avoid exacerbating the issue.

I am using the USB cable that comes with the Intel Realsense cameras. I have tried updating the firmware with the fw-update.exe tool from the command line, as well as using the latest Realsense Viewer.  

I can update the sensors to the latest firmware version 15_5_0_2.  However, even after updating to that version, if I try to then roll back to 5_12_7_100, the same symptom occurs.

I need a couple of things:

1) How can I un-brick these sensors? How can I access the recovery part of the device to install a working version of the firmware? I have dozens of sensors that are essentially broken now.

2) How can I get the version of the firmware I need for my software to run properly installed on the sensors?