I recently picked up a cheap PSone to replay some of my old favourites (the original PlayStation was the first console I chipped – to play Metal Gear Solid USA Import!). I soon realised the PSone wasn’t as easy to chip to play imports as the original shaped PlayStation console, most of the modchips for sale (or their code to download) only allow CDr copies to work, if they are the same region as the console.
I then found out about the ONEchip and found the code to download. The same site also sell flashed chips and have installation diagrams. I also found A LOT of information on Fatcat website. I did have a link for a modchip that works in NTSC consoles too (allowing using of imports), but have lost it :-(
I found a bunch of other diagrams too, and ended up with dozens of images, with slightly different options, so in the end made my own.
The ONEchip is a stealth chip, so it will go to sleep after a short while. To use it, it’s easier to pop your import game in, then switch your console on and let it load the import. It is currently only suitable for PAL consoles (although looking at the code before programming the 12c508a chip, it looks like it could be altered!)