PSX backups on softmoded PS2?

[Temporary]

I've got softmoded fat ps2 with HDD. Since my original ps1 crapped out I was wondering how to play PS1 backups on PS2. I read bits and pieces here and there about swapping psx disks in browser menu, but that supposedly only works with certain versions of PS2 (my hangs on psx logo)
Then something about elflauncher file that would have to be added soemwhere, but I could't find any concrete info or step by step, just bits and pieces.
Anyone can shed some light?
Thx!

[TnA]

There are only these methods:

1. Disc-Swapping:
You need an original PS1-Disc and a PS2-Version SCPH 500xx and up, or a PS1-Swap-Disc.

2. ISO/Images/PS1-Emulator:

Only a preview is available and there is no sound in it yet,...
Don't expect games to run, even thought it's compatibility seems to be quite good for a preview.

[iwasaperson]

3. 390xx and down: do the double swap trick done on the ps1 (works, confirmed by me on the SCPH-35001).

[TnA]

Warning! The double-swap-trick will harm your drive for sure...

1. The double-swap-trick is only needed on models prior to 500xx. It might be possible to load backups with a single-swap on those older models, too.
2. Another way is to use a PS1-Swap-Disc on those older models, so no double-swap is needed and the disc should stop spinning, before swapping...