I can login with my firmware password but then I cannot turn it off in the recovery mode.
When I enter it again it fails.
MacBook Air 13", macOS 10.15
Try using an external USB keyboard just in case on of the keys is bad. Even a Windows keyboard will work. Otherwise there is no other way to disable or remove the firmware lock without Apple's assistance (with valid proof of purchase).
If you want Apple to disable the firmware password you will need to take the computer to an Apple Store or an Apple Authorized Service Provider along with valid proof of purchase. Apple has very strict requirements as to what constitutes valid proof of purchase. Here is the Apple article regarding firmware passwords:
https://support.apple.com/en-us/HT204455
Edit: Make sure the Caps lock is not enabled. Try using an external keyboard to enter the password in Recovery Mode just in case the keyboard isn't working correctly.
So I cannot disable the firmware password myself?
Caps lock is not enabled, the keyboard works for entering Recovery Mode, it's when I try to turn it off it doesn't work.
Same issue with external keyboard.
I can login to Recovery Mode, but I cannot change or disable it.
Cannot turn off firmware password
