Burning PS1 iso to play on PS2 with chip

Hi guys,
what are the guidelines for this? I want to burn a ps1 iso to play on my ps2 which is chipped. And I don't think I can load them from USB can I...?
Do I have to use CDs or can I use DVDs? Is there a special max or min speed I should use, what files MUST it contain etc.

Thanks.

CD's must be used

Even if you could play from USB, USB on the PS2 is so slow there would be issues with most games not being able to stream the data fast enough

CD images must not be *.iso format because of the limitations of that format, but common ones are bin+cue and img+ccd (sometimes they come multiple bin files and a cue or bin+wav files and a cue) both cue a cdd files are descriptor files and that is what you burn from, they are tons of other CD disc image formats though too many to list

The other option is via Pops emulation for PS2 but you need to be running that from an internal IDE HDD (Not from a USB HDD)