Well to play import PS1 games on my Messiah 2 chipped PS2, there is a method.
Turn your PS2 off.
Push down and hold the front power button untill the light on the eject button comes on.
That turns off the main part of the modchip, but it also allows you to play your import PS1 games, actually you have to do that to play your own region PS1 games I think.
If that doesn't work, you might want to search on google about the Messiah 3 chip.