keyboard not working on booting


İ install angstrom demo.
When angstrom starts, there is no problem, keyboard is working.
when i see "Hit any key to stop autoboot" message, i press keyboard
but it dont stop.
i remove sd card, so angstrom dont start and i see prompt.
But but keyboard dont work again.
i remember, it was working before.

my x-loader version is 1.4.4. There is problem using U-Boot 2010.03. i
want to erase NAND and install 1.4.4ss.
i cant do it beacuse my keyboard dont work at prompt.

what must i do?