ps2 modchip to play psx

[RCBH928]

Is this possible?
I know a guy that has a modded ps2 that runs backup ps2, but is it possible to play psx backups?
Like can I download a game off the net ,rip it on a CD, and then run it off the ps2? I am thinking of buying off him thats why, i never owned a ps2.

Problem is I once inserted an original psx Casper game into a modded ps2(which did play backups) but it didn't run. I am not sure why was that. The cd even had the black dye

[Krooner]

There's a different boot procedure for pirate PS1 games, but not all chips will run them, I have a Messiah 2 and I've to turn on then press and hold reset for 3 seconds.

All chips a differnt though so find out what chip it is

[RCBH928]

am I supposed to open it up to figure which chip is it?

[zerexerez]

I guess you can test try on it without opening it up, hopefully it doesn't activate some other command? ^^;;

My modded PS2 requires me to hold the reset button to play PS1 games/backups or DVDs, and I usually hold it till the the end of boot screen I've read elsewhere that sometimes it needs pressing reset twice(or is it trice) to activate it, dependent on the modchip. Latest modchips do direct boot, like my friend's slim.

[executioner]

First time I've tried in all the years of having mine and it actually booted a psx backup. My ps2 never ceases to amaze me.