A man calling himself “Dr. Abrasive’, more than twenty years after the release of the Sega Saturn, has found a way to crack the device’s copy protection. He started working on this project in 2013.
dr. Abrasive says in an interview that he became interested in the Saturn at the time because of the chiptune capabilities of the multichannel sound chip. He then wanted to write software for the device, but ran into copy protection. This proved to work well, because the system detects a wavy line in the outer ring of the CD-ROM. This cannot be copied with a CD burner, because empty CDs are already provided with a spiral.
He then focused on the hardware of the Saturn. This turned out to be quite extensive. For example, the device has two main CPUs: one for sound and one for the CD subsystem. Reading the ROM of this chip with a microscope was never successful, because it was made with the ‘implant ROM’ technique, says Dr. abrasive. After he got his hands on several schematics of the cpu for the CD, he took the cpu apart and placed it on its own board. As a result, he was eventually able to read the entire contents of the ROM.
Through extensive reverse engineering, he found a kind of backdoor for developers in the code, among other things. However, he decided to turn his attention to the video CD jack on the back of the Saturn. An add-on card could be connected to this to play such CDs with the device. In the ROM of the card, he found random-looking code, which turned out to be encrypted. This code was also found to run on the Saturn’s internal CD-CPU, which is completely isolated from the rest of the system. By choosing to ignore the device’s CD drive and develop a flash card, he was eventually able to plug in his own USB stick.
This allows enthusiasts to rip their CDs via a PC and still play on the Saturn with a USB stick, says Abrasive. There is a need for this, because the CDs become less readable over time.