So I recently inherited a Nokia 2.1 from a relative who passed. I don't know the pin code, nor do I know the Google credentials 0needed.
When I enter recovery, Fastboot mode is not selectable and is in red text comparet to the other text. I did manage to get ADB to recognize the device in sideload mode, but when I try flashing the stock Android rom i downloaded it gives me the error message: "Signature verification failed (Error 21)".
So I can't enter Fastboot for some reason, so I can't use Fastboot to flash TWRP and after that flash my ROM, and I can't use sideload to flash because of a sinature verification error.
What do I need to do to be able to flash TWRP/a stock ROM and get this phone running again?