D2C

From Nintendo-Scene Wiki

The D2C chip is the DVD drive controller chip found in the Wii. It is a DVD Drive controller chip similar to the D2A, DMS, and D2B also found in some Wii Consoles. There are several known “back doors” in the Wii controller chips that allowed Wii modchips to work. These backdoors are accessed through a sort of secret serial port that exists on both the Wii and Gamecube. Some teams have claimed that all of them have been removed in the D2C version. Others have speculated that the pins of the chip that make up the serial port and are needed to connect a modchip have simply been cut internally.