[hackrom Pokemon Red++] After loading a savestate, saving the game doesn't update the .SAV

[RafaelTrepaUnCarballo]

Latest mgba Build: 0.10.7172-cb9f7 (both Switch and win64 versions)
Hack: Patched rom red-plus-plus-v3.0.2-hard

I was playing normally, first in my PC (in BGB) and later in mGBA on my Switch. mGBA recognized the save, I could play an hour, saving without problems...

...but at some point at the end of Mt Moon, after saving and loading some savestates in a short time, mgba stopped updating the battery file with my save file. I kept playing until Misty, then saved and savestated. The next time I opened mgba, my progress was gone.

I uploaded the last savestate, saved the game, but as soon as I closed mgba or hard-reset the game, the game loaded the outdated battery file instead of the save after loading the savestate.

The same behaviour happens in mGBA PC: I can't do a permanent save after loading a state in this hackrom

red-plus-plus-v3.0.2-hard SAV and SAVESTATE.zip

[endrift]

This is sort of unfortunate because the problem is that R++ is perpetually writing to the save file, and mGBA tries to wait until 15 frames after a game finishes writing to the save file before flushing it to disk. There is, however, a bug whereby when you load a savestate it won't write back the save file at all if it's never flushed after a save finishes. This is fixed in a commit I'm about to push, but it does mean that it won't get flushed to disk if emulator crashes. Further, it means that even loading a savestate will overwrite the save on disk because mGBA can't tell the difference between using the save as extra RAM and using it to actually save the game...