Sega (and Nintendo) continued using schemes similar to the one at issue in Sega v. Accolade, but requiring the reproduction of the companies' respective logos.

Sega (and Nintendo) continued using schemes similar to the one at issue in Sega v. Accolade, but requiring the reproduction of the companies' respective logos. This is why the Nintendo logo on classic Game Boy systems is replaced with a solid block if you turn the system on without a cartridge; the displayed logo is read from the cartridge so that publishers would have to reproduce it. Nintendo also did a low-tech version with Famicom Disk System: there was a plate inside the drive embossed with "NINTENDO", (notionally) requiring a matching engraving in the disk's enclosure. In Sega's case they even devised a scheme of formatting bit patterns on CDs to produce a Sega logo visible to the naked eye, and then checking for the presence of those patterns to decide whether to boot a disc. I think the idea was less about making the compatibility token more copyright-worthy and instead making it a distinctive trademark so that Nintendo and Sega could go after bootleg manufacturers under various trademark laws.