Whether for warranty purposes or for getting the damn Revolut app to work.
Firstly, disable Windows driver verification (for Win 11).
I didn’t do this initially and installing Sony’s Fastboot drivers in normal fastboot mode didn’t work for me. It did get ADB working though.
So I did adb reboot bootloader with the cable attached to Windows. This seemed to put my 10 iii into a different fastboot mode. It suddenly introduced a new “Android” device (without drivers) in Device Manager.
I then reinstalled Sony Fastboot drivers.
For me, the last step made fastboot oem lock work. When booting, it erases (Android’s) user data. I think this breaks Sailfish and Sailfish cannot be installed if the bootloader is locked. I might test the former later.
I don’t know if this reinstalls the original camera filters and they talk about it not restoring the individual device key. A better chance of reinstalling the original camera filters is using NewFlasher and your new firmware’s .TA files but be careful. Do delete the persist*.SIN file and do back up your TA firmware (& re-run).