[IronBacon]

The details are explained on the Cturt blog mentioned in another post, the original researcher, this one seems a GUI to simplify the process of patching ISO.

About your questions, I would guess transforming PS2 CD title to PS2 DVD first could work.

For PS1 titles, with a different exploit (mechapwn) you could boot them, but read the fine prints as it basically convert a consumer PS2 to a devkit/testkit (DEX?)...