Thinkpad help - firmware update bricked battery?

(I hope this fits this community, if not I’d be glad to know where I can post it) Updated my firmware on my thinkpad t580. This made my external battery (3rd party) jump from 64.8 Wh design capacity to 40.4 Wh design capacity (but the computer doesnt turn off when it is “empty”, this is a software bug). AI’s theory: The firmware update made the system stricter towards 3rd party batteries, blocking it and reporting a dummy number. This is plausible because after the firmware update the battery is no longer reporting its mAh (used to display 6000 mAh). Rolling back to my previous firmware version (which is supported on thinkpads via fwupd downgrade) didn’t fix it… Has anyone experienced something similar? I also tried downgrading my kernel (hoping that an older kernel wouldn’t suffer from this for some reason) but it didn’t fix it. Guesses or fix ideas that might break something are also welcome, I’m using NixOS.