One of our customers with the above issue sent us the following email in a support thread, and hopes this can be used to help others:

"I have found a workaround:

while the radio wasn’t turning on, I noticed that when plugging the usb data cable the left orange led (button 1) turned on.

So I plugged the cable and follow the procedure to get into the bootloader mode.

While the screen was off and nothing apparently happened to the radio, OpexTX companion has been able to re-flash the device

now it works as expected."

(Credit to our customer Andrea for figuring out the above workaround! Thank you!)