Swap Trick Information:

There are multiple ways to perform a swap trick but they all have in common that an original Playstation CD-ROM is in the drive during the security check and then is changed to the Import or Unlicensed disc while keeping the lid sensor switch pressed down with an object. The most popular item to use is a spring, possibly from an old ink pen, so that the lid can be closed after the swap has been completed. Below are some of the different ways to do a swap trick. But first some potential problems.

Swap Trick Problems:
When you perform a swap trick it causes some problems. During the initial spin-up of a disc the Table of Contents is read into memory inside the cd controller. The table of contents contains the number of tracks on the disc and the starting time code for each track. When you swap a different disc into the drive the table of contents is not updated. This will cause games which use CDDA (audio) tracks to be unable to play back their audio properly or at all. Another problem that can affect later model consoles is during the original spin-up the laser does calibration to read the disc optimally. When you swap to a different disc it does not recalibrate and may have a harder time reading the disc. These problems can be addressed by modern homebrew programs such as Stealth Unlocker and TonyHax International.

Swap Trick Improvements:
The problems mentioned can be fixed and are fixed in the two programs mentioned above. There are CD Commands which make it possible to read the Table of Contents from the disc after spin-up as well as to recalibrate the laser on vC2+ cd controllers. More information about this below.



Swap Trick Methods

BIOS CD Player Menu:
The included CD Player feature was the first method for doing a swap trick due to the extreme simplicity. Start the machine with the lid open and select CD Player. Place an original disc in the drive and engage the lid sensor with your spring or other object. The disc will spin up and the security checked. Afterwards the disc motor will stop and the disc can be replaced with an Import or Unlicensed disc. When the CD Player is exited the cd controller will report that the disc in the drive is licensed and then the console will load the disc. This method of swap trick was fixed in BIOS version 2.1 for all regions.

In BIOS versions 2.1 and newer the cdrom controller version is checked. If the controller is vC1 (b)  or newer the BIOS will issue the CD command ReadTOC after exiting the CD Player menu and also before the game program is loaded. ReadTOC causes the disc security to be checked again as well as reading the table of contents from the disc. This is how the CD Player swap trick was removed from newer consoles. However as proven with my project Stealth Unlocker, removing the ReadTOC commands from newer consoles restores the swap trick.

Your console will support the CD Player swap trick if your BIOS version is 2.0 or older, or if your cdrom controller version is vC1 (a) or older.

Cheat Devices:
There were many cheat devices like GameShark, Pro Action Replay, Goldfinger, and clones which could enable a similar swap trick to the CD Player Menu. The steps are the same, the method of causing the CD motor to stop spinning is all that is different. One of my Cheat Cartridges you would go to its own CD Player menu to get the disc to stop spinning. After swapping you'd navigate to the option to Start Game to get the disc to load.

Hot or Live Swapping:
It was also possible to perform a swap trick while the machine is booting normally by watching for a pattern of disc spinning speed changes and swapping between an original disc and your import or unlicensed disc. This is a more risky method and also more difficult to perform correctly. I personally wouldn't recommend using it unless you were doing so to install some other method of booting unlicensed discs using a CD-R.

Demo Swap:
The last method I'll mention is the Demo Swap which uses a program I wrote, TonyHax, and an original Demo Disc. You'll need a supported Demo Disc such as one of the many Interactive Disc Sampler Vol # releases. You create an ISO image of the disc and then patch it with the DemoSwap Patcher program and then burn the modified demo to a CD-R. Then the process is to boot the demo disc as normal and then get to the specified point for that demo disc where you can safely remove the disc from the drive. This does involve grabbing the spinning disc but if you quickly remove it then damage is unlikely. You wait for the drive to stop trying to spin and then place the CD-R version in the drive. Then you follow the next instruction which is probably exiting a demo and loading a different demo. This will load TonyHax which will unlock your drive's security and allow you to place another Unlicensed disc in the drive normally and then boot it. This method like the hot swapping is recommended solely for installing another method of booting discs such as Stealth Unlocker on a Cheat Cartridge or TonyHax onto a memory card. Stealth Unlocker has an installer CD image, and TonyHax can be installed on a memory card with my MCTOOL program which can be burned to a CD-R.



More random information

The swap trick's Table of Contents problem can be solved by using a command called SetSession. This command is meant for being able to use multi-session discs but it doesn't seem like it was ever used for this purpose. However it can be used to select the 1st session of the disc after using a swap trick which will cause the ToC to be read from the new disc without the security check being performed again. The command ReadTOC will also update the ToC but it will cause the security check to trigger.

Unfortunately the SetSession command is buggy on the first 3 known versions of the cdrom controller known as vC0 (a), vC0 (b), and vC1 (a). These versions of the cdrom controller will not properly update the ToC. I did many tests to try to figure out a way to get it working properly. The first working fix involved sending the SetSession command rapidly and then examining the ToC data returned by the GetTN and GetTD commands. While this worked it could take somewhere between 2 and 5 minutes before a disc with a lot of audio tracks would have its ToC read in correctly. I eventually found a much faster way to get around the bug which ended up being far more simple and faster. By changing the current session to something besides the 1st session and then going back to the 1st session the command would properly update the ToC in a normal amount of time. This was very important for supporting early Japanese consoles in Stealth Unlocker and TonyHax International as they lack the secret unlock of their overseas counterparts and must use a swap trick to play imports and unlicensed discs.

The vC0 cdrom controllers appear to have only existed in Japanese consoles (SCPH-1000). The vC1 (a) controller was in both Japanese (SCPH-3000, SCPH-3500?) and early American consoles (SCPH-1001). It was also in early PAL consoles (SCPH-1002).

Starting with cdrom controller vC2 the performance of the cdrom drive seemed to improve. Japanese model SCPH-5500, American model SCPH-5001, and PAL model SCPH-5002 may be the first units to contain a vC2 cd controller. These controllers will automatically adjust mechanics of the laser assembly for optimal reading performance. As mentioned above there is a laser calibration sequence on disc spin-up. Using a swap trick will not allow the drive to calibrate to the new disc and can lead to reduced reading performance. I personally tested this on a vC3 console and found that by using the correct cd command to trigger the laser calibration sequence after the swap then the very same disc had extremely better performance. The test was done using the game Slayers Royal which has an opening FMV. Using the swap trick as normal to play the CD-R resulted in many FMV stutters. It was extremely poor performance. Testing again but executing the laser calibration command prior to launching the game resulted in the exact same disc on the exact same console to have no FMV stutters at all.