I hate Windows for various reasons and this is one of them....
You can download a Linux Distribution from the Windows Store and try with that again. Before you do that you have to enable Windows Subsystem for Linux in the Control Panel. Did you try to run the cmd.exe as an admin? Yes, you might...
I am not completely sure about this, but try to run the command line as administrator. You can always do a ,,fastboot devices" command to check for the currently discovered devices. Did you enable the unlocking in the developer settings?
Thank you for your kind words, I really appreciate it!
unfortunately it seems the only way to flash a ROM is through fastboot or SP Flash Tool after unpacking the super.img and replacing the system.img with a GSI. You can find more info and detailed descriptions in the mentioned thread.
Offline charging and bluetooth audio is kind of a GSI bug as always, but I am afraid that the fingerprint reader will be Umidigis fault, because it is considered an obscure proprietary hardware. I suppose even, if I unpack and repack the super.img I won't be able to get it working, the GSI won't...
I will also try to build a more up to date version of TWRP when more commits arrive on GitHub. It would be good to be able to resize the system partition from TWRP, so we don't have to touch or remove the /product partition.
I am still not sure, look at this screenshot!
I mean in general this is really not a big deal. GSI ROMs tend to act a little weird with partition layouts, anyway.
The big deal will be a working TWRP in my opinion.
I just saw that it has been removed from the link. Fortunately I saved it, too! Here it is in my MEGA drive: QCN
Don't forget to edit it, follow the tutorial. You have to input your own IMEI numbers, otherwise it will not work.