PlayStation Development Network

I know that the PS1 has no MagicGate support and thus can't read/write PS2 saves. However, is MagicGate required to access the card at all, or could one write non-encrypted files to a PS2 memory card, and access them from a PS1?

Just cut an extra notch in the PS2 card edge connector. I guess everything else could be solved by software; if the PS1 software is programmed to work with PS2 cards.