Some Playstation games have additional protection to prevent copying and importing. I will give some detail on SCEx modchip detection, secondary disc check, disc swap, and LibCrypt. The game Spyro Year of the Dragon contains additional protection.

SCEx Codes:
Security Wobble:
Original discs are believed to utilize the tracking circuitry of the CD-ROM to generate the SCEx code by having a section near the beginning of the disc track spiral 'wobble' back and forth in a manner to encode the ASCII characters for the SCEx code. During the spin up process if the CD-ROM controller does not see the correct SCEx code it will not allow Read commands as normal and the GetID command will inform the software the disc is not licensed and not boot.

Swap Trick:
One of the simple ways around the SCEx code check is a Swap Trick. An original game disc is inserted into the CD-ROM so that a legitimate SCEx code is read and then the disc is changed while keeping the lid switch sensor pressed so that the drive controller is unaware of the change. See here for more detailed information.

SCEx Modchip Detection:
The most basic modchips will send one or even all three of these SCEx codes constantly. This allowed the early protected games to easily detect the modchip. Normally a protected game will seek to some position in the middle of the disc and begin reading. It will then reset the SCEx Counters in the CD-ROM controller which keep track of how many SCEx codes were received. After a short time it will then read how many SCEx codes were received. Without a modchip it would be zero.

Secondary Disc Check:
After the first protected games were released someone realized they could bypass the protection in these games if the modchip was turned off either by a switch or by a timer so that the game could boot up but the modchip wouldn't still be sending the SCEx codes once the game started. So in order to prevent this easy work around the protection routine evolved. The new routine would first issue the command ReadTOC. Despite its plain name the command does more than reading the Table of Contents from the disc. ReadTOC also resets the disc security authentication and checks for the SCEx code again. This means you cannot simply turn off your modchip because the secondary disc check would fail and the game would stop at the Software Terminated screen. Another effect of the secondary disc check is it combats people who were using a Swap Trick to play the game.

Disc Swap Protection:
Some games appear as though they attempt to detect if the game was booted using a swap trick. The game will usually read the total number of tracks with command GetTN and then using command GetTD it usually checks the timecode of a track. If an unexpected response is received it will trigger the protection. Normally when doing a swap trick the Table of Contents from your original disc is still in memory and not the Table of Contents from the disc you swapped in. This check seems unnecessary in some games due to the secondary disc check updating the ToC and rechecking the security code but I believe this is done for the Early Japanese Consoles. See the swap trick information page.

Early Japanese Consoles:
The earliest Japanese consoles have vC0 CD-ROM controllers. These controllers do not support the ReadTOC command and so the secondary disc check is not possible. 

LibCrypt:
This protection was used primarily and I believe only in PAL regions. It was absolutely not used in Japanese releases because the first CD-ROM controllers don't support the subchannel reading commands required for this protection. In theory it could have been used for American releases but I don't believe it ever happened. The basic idea of LibCrypt is the discs were mastered with bad Q subchannel data that would be read to recover a 16-bit key which would be used to decrypt game data. This worked because many CD writers and copying software would not replicate this modified subchannel data. I believe if you use the right software and your writer supports it you can burn a copy with this data intact and not be bothered by the protection. Some LibCrypt protected games may also be modchip protected.

Stealth Modchips:
These chips are designed to pass all the previously mentioned checks by mimicing the correct behavior of using an original disc. They should only generate the SCEx codes at the appropriate time.


Below are listings of protected games. This is not necessarily a complete list.

Protected North American Games:
Protected Japanese Games:

Spryo Year of the Dragon Protection:

This Spyro game has the same protection as later games for detecting modchips and swap tricks. But unlike any other game it has layered checks to detect any changes to the program. This is sometimes called anti-crack protection. If you remove the code that checks for modchips then other parts of the game will behave differently. You can still play the game but you'll be informed early on that your game is hacked and may not work properly. See the article at TCRF for more details. The early cracks for the game after its release all triggered this anti-crack protection and it was around 2 months before the group Paradox released a fully working cracked version.

While developing Stealth Unlocker and focusing on support for Japanese and Asian consoles I discovered how the anti-mod patch from TonyHax was not going to work for the asian consoles. I had to develop my own patches for bypassing the protection routines in games for them to work. Because of this I had to do my own crack or patch for Spyro. I came up with my own solution for the american version and implemented it into Stealth Unlocker. Afterwards I thought it might be useful and would be fun to turn that into my own stand alone patch that could be applied to the ISO. As an added bonus this may be the first crack for the revised version of the game which has important bug fixes. I did try taking a quick look afterwards at the Paradox crack to see how they dealt with it and as far as I could see they may have patched the Kernel in some way to deal with it. I didn't look much closer than that. The TonyHax anti-mod patch is also a Kernel patch but as previously mentioned it would not help on the Japanese consoles.

MottZilla's Spyro 3 Protection Patch