Does your console have a modchip? It could be that your modchip is confused because the bootup sequence of your Playstation 2 has went of the 'usual' routine for most Playstation 2 consoles out there after FMCB is installed.
Originally Posted by uomoartificiale
FMCB will cause your Playstation 2 console to take a detour before booting rom0:OSDSYS. If your modchip is monitoring for certain events, it might become confused. Naturally, that depends on how the modchip makers designed the chip to function.
In that case, try disabling your modchip and try again with some legit Playstation games.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS