[charlie_ps2]

There are limitations in what can be achieved with this automated knife/card swap. There is no enhance mechanism for getting the timing right and "fooling" the PS2 in an orderly way other than the tray being forced out.
With the knife/card trick there were many games that wouldn't play.

So barring a laser that's differently calibrated from your mate's chipped PS2, it's likely to be the boot method that's the problem - the limitation of the R-Chip.