@Doraemon,

You can contact bplan to obtain an update of openfirmware. Indicate the revision of your mother board, the serial number of you cpu daughterboard and the version/revision of openfirmware on your pegasos 2. With this update of openfirmware you will be able to use usb keyboards instead of ps2 one. And it will not stop/block the start on bplan logo. Find their adress and send a mail.

Good luck.

Brumiga