LP#1289748 has my progress, but so far it looks like the EC is coming up with zeros. It’s been an educational experience getting to that point, but I’ve no clue where to look next. Is the EC unhappy with something Linux is doing/not doing? Do I just have two faulty batteries and/or a faulty machine? Who knows. No, seriously, who knows? Any help would be appreciated.
Future challenges include: set up the Crucial m500’s built-in encryption (not officially supported, of course).