I'm pulling my hair out here. Doesn't matter what I do, the APU will not start since updating today. I've done a bunch of flights in this airplane, I'm familiar with the procedure, I have started the APU successfully several times.
Battery on - Fire test - PWR/FUEL - wait for door to be open - Start.
Loading cold and dark (not setting via EFB), do the things listed above, nothing happens. No mention of the APU on EICAS, APU Door state remains ----, No symbology ever appears. I have tried just waiting like 30 seconds after pushing PWR/FUEL and starting it anyway, nothing.
Even when I click the "Ready for Startup" preset on the EFB I can't start it. The Door state switches to open and I get the symbology, but when I actually try and start the APU nothing happens, no EGT rise, nothing.
There is fuel in all 3 tanks, everything looks correct, but the APU refuses to start.
I have uninstalled the CRJ, downloaded the updated version from the store, re-installed it, still can't start the APU. Perhaps worth mentioning as I suppose it could be related, but if I switch the state to "Ready for Taxi" in the EFB, or any powered state, if I switch it back to "Cold and Dark" everything doesn't turn off. All the displays are still powered, CDU is still powered, FO radio stack is still powered.
Edit: Want to mention I originally updated the airplane via the ASU updater.