I am not sure about the terminology here, apologies if I am confusing but happy to try and clarify.
I had an old motherboard die and needed to get a new mobo/cpu for my TrueNAS Scale system. I am directly connected with keyboard and monitor. I can boot to GRUB and see all the installed versions, but upon selecting any of them I get a quick 2 or 3 screens worth of command line flash by really fast and then the screen goes blank. Does not show up on my network so can’t connect to webui.
I’ve tried disabling secure boot and CSM. Also saw a thread about memory issues so tried with a single dimm. Not sure if it is a configuration issue or if the hardware change is just too significant?
I’ve once encountered an issue where some NIC setting was rendering the boot environment non-functional. Perhaps a hardware change could possibly have the same result.
You can make a fresh truenas installation on a different drive (don’t forget to disconnect the old boot drive). Then acquire the configuration from the old boot drive and finally try to restore it.