Is it possible that you have Hijack's "Force AC/DC Power Mode" setting set to DC?

That was my first thought, too. But I think some of the things he said indicated that this was not the case:

He said can't even do an upgrade from a cold start on AC power, and the upgrade happens before Hijack takes over. I think he also said that he installed hijack and tried to force AC and he still couldn't do an upgrade even when he did that.

So I think it really does sound like a hardware issue of some kind.

(But Alex, check that anyway, just to be sure.)