Leif and Ard,
I have the branch "rfranz-backspace" on http://git.linaro.org/people/roy.franz/uefi-next.git that I'd like to get you to try to make sure it works with other setups. This should also fix the delete key. I still need to look more at how EDK2 determines which console type to use, and if I need to conditionalize any of this based on terminal type.
The backspace 'fix' is to treat both 0x8(^H) and 0x7f(^?) as backspace. This is done by changing 0x7f values to 0x8 during the console input processing. This is similar to how u-boot treats both values as backspace - delete doesn't work.
Fixing the delete key is a big more involved, many (most?) linux terminals use the vt220 escape sequence [3~ to do delete. Right now EDK2 only handlings 2 byte escape sequences, so the state machine needed to be extended. This is a very 'linuxy' change, so I don't know how popular it will be.
I need to try the patches with a windows based terminal emulator, and I suspect I'll end up with the delete key being backspace, and there really being no delete.
Thanks, Roy