ModChips | Software Hacks | Disc Swapping
How does it work
PS2 games have the ability to load ELF files inside the disc, as long as the inserted disc is verified. Once the PS2 verifies the disc, it starts by loading the ELF file pointed to by a SYSTEM.CNF file inside the disc, from there on the game has the ability to do whatever it wants, as there's no real Operating System, the game runs on bare metal, the only check the PS2 does from now on is on the laser sensors (which vary depending on the model) to know if the tray has been opened or not. Swap Magic takes advantage of this.
Swap Magic is a pressed disc that the PS2 recognizes as legit (how they managed to press PS2 discs is beyond me, but unofficial pressed discs have been existing since the PS1 era). The PS2 reads SM's main ELF and loads it as any other game, and this is where the fun begins. Swap Magic has a set of intentionally bad sectors where some files are supposed to exist, when Swap Magic tells the PS2's CDVD drive to read these files on such bad sectors, it fails, the PS2 keeps retrying but is eventually unable to read them, causing the CDVD drive to stop both the laser and motor, so the disc stops spinning. This allows the user to then easily swap Swap Magic for another game, be it a backup or an import, as long as the tray's sensors are all blocked and the PS2 doesn't know that the tray is being opened, then you can easily swap it.
Once the disc has been swapped, Swap Magic's main ELF is still in memory, so it doesn't stop Swap Magic from working, the user can now tell Swap Magic that it has changed the disc, Swap Magic then proceeds to read the disc's SYSTEM.CNF file to obtain the filename for the main disc ELF and load it like any other game can load an ELF.
Swap Magic works due to two reasons: the PS2 stopping the CDVD drive when a bad sector is being read, and the user's ability to swap the discs without the PS2 knowing, as long as the PS2 doesn't know the drive is being opened, it doesn't recheck the game. It's a pretty clever hack that many people used in its time, and it's still being used.
Little Known Fact: Swap Magic still works even on the PS3, even on the latest PS3 firmware! Although Sony did patch the swapping method, you can still use Swap Magic to load an ELF from USB and launch your favorite PS2 homebrews on your PS3 in HD glory, something very nice for people like me who have no other way of running homebrews on the PS3.
by Acid_Snake | wololo.net/10-days-of-hacking
So you might think why do I need SwapMagic when I can just use any game for that?
Well, swap magic makes the rotation stop first so you can easily change to the disc you want without harming the drive. Once swapped you can then simply press x to continue without any hurry.
Additionally you won't need to tape your PS2 to trick it to spin the disc when opened.
Tutorials & Guides Compilation
[Tutorial] How to do the PS2 Disc Swap Trick and play PS1 Games (via youtube.com/FPSGamerz3)
[Tutorial] Use Swap Magic 3.6 with PS2 Slim To Play Backed Up Games (via youtube.com/ProjectPhoenixMedia)
[Tutorial] Install the Tape, Tissue, and Straw Mod for PS2 Slim (via youtube.com/ProjectPhoenixMedia)
Frequently Asked Questions
|
|
Can swapping discs destroy my drive?
Yes. So be very careful, or better buy SwapMagic!