Upgrade from 12.0-U7 to 12.0-U8 fails to reboot - framebuffer error

[haywooj]

Everything running peachy on this SuperMicro rig:
SuperStorage Server 6049P-E1CR24H (Supermicro X11DFH-T board, latest BIOS)
Xeon Sllver 4114 @ 2.2GHz 96GB RAM, 13 x 10TB, 2 x 256 NVme startup drives

Until I performed the 12.0-U7 to 12.0-U8 upgrade where the System now won't boot and halts on the EFI framebuffer information display (see attached)

1. I have tried reinstalling, reverting from 12.0-U8 regressively back to 11.0-release. However to no avail except for 11.0-release which I hesitated to install as it uses GRUB bootloader instead of the newer loader
2. I have also tried to boot directly into the system via the UEFI shell
3. I also installed to an SSD using another machine, moved the SSD to my server and tried to boot - not happening

I have seen references to this on both the TrueNAS forums and the FreeBSD forums, where it has been acknowledged as a bug, and a possible patch provided - but this is a bit beyond me I must say.

So now to some questions on how to resolve this:

1. If I set my BIOS to Legacy, I can boot the installer and it offers to install to my current 2 x NVMe (former boot) drives. If I do this will I still be able to import my existing pool, or will the switch to MBR lose the drives (I have the config backup)
2. Some references were made to trying to install via serial - I can't find instructions for this (settings, XOR, 9600-N-1? How To?
3. Does 13.x fix this issue and so should I wait?
4. Other suggestions as to how to get this box up and running with my pool intact?

Many thanks

 

[haywooj]

To reply to my own thread, in case anyone searches
In the end Supermicro Tech support recommended clearing the CMOS by removing the battery and shorting the pins (page 61) :
https://www.supermicro.com/manuals/motherboard/C620/MNL-1912.pdf

The only thing I would add is that this clears the BIOS of both the board and the AOC-S3108L-H8iR SAS card (an LSI 3108), so there might be some adjustments to make there.

My servr is running, and now I'm searching for the IT firmware for this card, and will post if I find it