PS1 modchips generally only had one purpose, to send the SCEx code to authenticate the disc. PS2 modchips had to patch certain BIOS related items and that is why those modchips often came with other features besides just authenticating your burned or import discs. That is also why PS1 modchips have something like 4 wires and PS2 usually had 20+.
There still are ways to modify systems but for PS1 it's separate from the copy protection entirely.