I updated my Mac Pro 5.1 from 12.6.4 to 12.6.5 today. The Mac Pro is running OCLP in a relatively recent version (a few weeks old, I can't say the exact version). OCLP is installed, along with a fallback partition with 12.6.3 on a SATA SSD. I updated 12.6.5 on the boot drive, an m.2 SSD.
Unfortunately, after the update, the Mac no longer boots. Unfortunately, and I was surprised, booting with the 12.6.3 partition doesn't work anymore either, even when I remove the m.2 SSD it doesn't boot anymore. The progress bar when booting the system always stops.
What I have already tried: NVRAM reset / PRAM reset. Unfortunately no improvement. Quite the opposite: Now the bar stops at the very beginning when booting the system.
Is there somehow a mode with terminal output at OCLP, so that one can identify possible error causes? Or do you have another tip?
EDIT: Seems, that the PRAM reset I did first, wasn't done correctly, because stupid me used the wrong keyboard for this. Second reset and it worked. Now it boots in all systems again (and I just saw that the m.2 SSD was never updated to 12.6.5). Next try now
EDIT 2: Update to 12.6.5 worked without problems now.