Almost screwed the pooch. Not sure what happened, but FPT flashing the fully modified UBU bios bricked it again. Had to use the badcaps bios to unbrick - it wouldn’t post with the FPT backup bios (with only microcode updates). Upgraded the bios with the latest Dell Vostro_3670_3070_2.33.0 bios, and then FPT upgraded microcodes again. That worked.
I’ve physically clipped the 16 pin bios too many times - it was very tough to programmer flash it back to life this time.
Don’t understand why programmer flashing the backup failed, but I’m claiming victory, and going to live with updated MC’s and older other bios drivers.