Modchip

They achieve this by either exploiting existing interfaces in an unintended or undocumented manner, or by actively manipulating the system's internal communication, sometimes to the point of re-routing it to substitute parts provided by the modchip.

Most modchips consist of one or more integrated circuits (microcontrollers, FPGAs, or CPLDs), often complemented with discrete parts, usually packaged on a small PCB to fit within the console system it is designed for.

Modchips typically require some degree of technical skill to install since they must be connected to a console's circuitry, most commonly by soldering wires to select traces or chip legs on a system's circuit board.

Memory cards or cartridges that offer functions similar to modchips work on a completely different concept, namely by exploiting flaws in the system's handling of media.

On the Xbox 360, a common modchip took advantage of the fact short periods of instability in the CPU could be used to fairly reliably lead it to incorrectly compare security signatures.

Other modchips, such as the XenoGC and clones for the GameCube, invoke a debug mode where security measures are reduced or absent (in which case, a stock Atmel AVR microcontroller was used).

Since modchips often hook into fundamental functions of the host system that cannot be removed or adjusted, these measures may not completely prevent a modchip from functioning but only prompt an adjustment of its installation process or programming, e.g. to include measures to make it undetectable ("stealth") to its host system.

[2][3][4] An argument can be made that a console system remains largely untouched by modchips as long as their manufacturers provide an official way of running unlicensed third-party software.

Most of the very few cases that have been brought before a court ended with the conviction of the modchip merchant or the manufacturer under the respective country's anti-circumvention laws.