Backing out port update that may have broken VirtualBox

I am no longer able to start any saved virtual systems.I get an error of
0x1 returned:

The virtual machine (any saved VM) has terminated unexpectedly during
startup with exit code 1 (0x1).
I suspect that a port that I updated this morning may be the problem. I
want to roll them back to the prior version, but I can't seem to figure out
how to do this. Can anyone with git knowledge tell me how I can do this? I
obviously can't revert the commits in the repo, but I need to do so to my
local clone to confirm which might be the problem.

Any clues? I have the hashes for the commits, but can't figure out how to
use them to revert the commit in my local clone.
-- 
Kevin Oberman, Part time kid herder and retired Network Engineer
E-mail: rkoberman@gmail.com
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683