R4 cartridge

R4 cartridge
The original R4 flashcard from 2007, with a microSD card.
Also known asRevolution for DS
DeveloperR4 Team
TypeFlash cartridge
Released2007
DiscontinuedYes; date undisclosed
Websitewww.r4ds.com(May 2008)

R4 (also known as Revolution for DS) is an unlicensed flash cartridge for the Nintendo DS handheld system developed by the R4 Team. It allows ROMs and homebrew to be booted on the Nintendo DS handheld system from a microSD card. This allows the user to run homebrew applications, to store multiple games and MP3 music files on a single memory card, and to play games that have been backed up or downloaded by the user.

The R4 Team stopped production of the original R4 cartridge. However, due to the popularity of the original R4 there are many other Nintendo DS flashcards using the R4 name despite the lack of any connection to the original. Some of these cartridges can also store a 3DS boot image; a 3DS can in turn be made to boot from the cartridge by way of an undocumented button combination recognized by the system's bootloader. Since the 3DS's secure boot signature validation has been broken, this provides a useful means of installing custom firmware on a 3DS.