I think Windows BSOD including QR code was pretty clever idea, although unfortunately it's halfbaked in that it's just a fixed generic URL instead of something specific to the error.
The problem with bootloaders is they really can’t spare a lot of storage. Storing different QR codes for all the common errors might be asking too much.
You don't need to store the whole QR code, just code to convert an URL into a QR code. Or a good, short URL that can easily be typed, e.g. "microsoft.com/errors/1234"