[SOLVED] RC2 @ symbol in top left corner

[rlogiacco]

I installed Xbian RC2 using the Windows installer but when it boots up I see an at character @ in the top left corner instead of the usual string "press shift key etc..." and I'm unable to get to the rescue console by holding the shift key on an USB keyboard attached directly to the RPi (no USB hub in between).
I need the rescue console to be able to switch from USB root filesystem to SD hosted one.

Any suggestion?

Raspberry model B, 8GB SD card.

UPDATE: the issue was related to my Cherry G230 keyboard which is not recognized at boot by the built in kernel modules, nothing to do with any misconfiguration or corrupted file.
I'm going to create a more relevant topic in the customizations category.

Thanks to everybody who tried to help me out.