Automatic update replaced BIOS with the wrong version, now I have no internal display on the laptop!

[Nilknarf]

Hello, I have a HP 15s-fq0017na which recently installed some updates automatically which in turn broke the internal display, external still works fine, and the interal display works when connected to another similar model laptop.

My suspicion is that it misdetected the model laptop I have and installed a BIOS for a slightly different variant, resulting in the internal display dissapearing. External displays still work, so I can plug it into a TV with the HDMI port, but that's obviously not ideal!

The problem is, the offical latest BIOS version for this laptop model is F.21, and the one that's currently on there is F.25, so I can't rollback to the previous version (using Windows + B + Power, it looks like its going to work, then fails). So the built-in BIOS rollback funtion fails, and trying to install the correct BIOS from windows says I'm trying to install an old version, so it's blocked. So I'm going around in circles because of a problem HP's own little software updater sitting in the system tray caused...

If I hit F2 on startup and check the system information, it says the System ID is 864F, but if I look at the .bin files from the BIOS update from the HP support website for this exact model, all that's in the extracted files is 0864A, 0864B, 0864D and 086C8, none of which match up, so I'm not even sure if I can trust the system information here now. If from the F2 on startup > firmware management screen I choose "rollback now", I instantly get "The system BIOS rollback failed. Unable to open BIOS signature file". I cna browse to another BIOS file to update from, but I have no clue where to get a 0864F.bin file which matches this system info from.

Could someone confirm what the system ID of this model laptop should be? And if it is indeed 864F, where I can get a matching current BIOS bin file from, and how I can actually install that when the version number is lower than the one on the laptop?

Any help or advice would be appreciated!

[Nilknarf]

Forgot to say, I obviously tried different display drivers (newer and older), which did nothing, but that wasn't surprising as the startup screens before Windows loads don't appear on the internal display either.