Serious issue with 25.30.0.20 - Multiples Bricked W52P

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There is a serious bug in relation to Yealink's W52P base firmware version 25.30.0.20. We've now bricked 4 units and have users down.
The original issue that arose was caused by inputting a remote phone book into the W52P with firmware v25.30.0.20. When the phone book was put in the place, the handsets lost communication with the base, and the Register Status on the Account tab, went from Registered to Unknown. I had the user reboot the handset which did not function. Then I had the user reboot the base station. After rebooting the base station, the base would not come back up and is now bricked. There were 7 units onsite total that were receiving the remote phone book. The first 1 was the process I listed above. Immediately after this occurred, I grabbed a spare W52P unit in the office to test. It was running 25.40.0.15. The remote phone book took and functioned fine, no "searching for base" message, or any issues whatsoever. I then tried with the latest firmware (25.50.0.20). This also functioned correctly. As soon as I tried to downgrade the unit to 25.30.0.20, the unit bricked. It was stuck on the firmware updating page for about 20 minutes before I pulled the power on the unit. Upon rebooting, the power light was lit solid but there was no other activity from any of the other lights. The unit is no longer able to be pinged, it is not accessible anywhere on the network, and the handset is not connected nor will it connect after attempting to de-register and re-register again. Plain and simple, the unit is dead.
Something to not, while trying multiple things to get the base to reset, I noticed if you hold the page key WHILE powering on the base, the power light goes lit, then the network, then the handset however the handset is still unable to connect and it is not accessible on the network. I think this started to put it into a recovery mode possibly? but there is no literature online referencing this so I was not able to fix the base.
At this point, it looks narrowed down to the firmware so rather than rebooting 1 of the other units at the customers site, I started the firmware upgrade process. Same result, bricked phone. Had the user reboot, and nothing, same as what I'm seeing here. So that's 3 bricked phones. The 4th one bricked when I plugged in a brand new, unprogrammed W52P, running 25.40.0.15. I just tried to downgrade the firmware to 25.30.0.20, That bricked the unit as well.
The remaining 5 or so functioning units at the customers site appear to be functioning AFTER removing the remote phone book string. I removed the string and the Register Status changed from Unknown to Registered again, with no other changes being made.

First and foremost, I need to know if there is a process that we can go through to "un-brick" the base stations, maybe some sort of a recovery mode? That would be ideal as the 2 units at the customers location are located in the UK (we're in California), so there is significant cost involved in shipping replacements AS WELL AS significant downtime to be experienced by the users if they have phones down.

Plain and simple, I need a fix, ASAP.