The modding scene of the Nintendo 3DS primarily involve custom firmware (software which patches the official firmware "on the fly"), which requires an exploit to obtain control of the ARM9, the 3DS' security coprocessor, and, secondarily, flash cartridges, which emulate an original game cart (which can be solely used to play untouched game cart ROM backups).
The current most widely used CFW is Luma3DS, developed by Aurora Wright and TuxSH, which allows unsigned CIA (CTR Importable Archives) installation, includes open-source rewritten system firmware modules, and exception handling for homebrew software developers.
3DS CFWs used to rely on "EmuNAND"/"RedNAND", a feature that boots the system from an unpartitioned space of the SD card containing a copy of the 3DS' NAND memory.
On May 19, 2017, a new exploit basis called sighax was released, replacing arm9loaderhax and allowing users to get even earlier control of the system, granting code execution in the context of the bootROM and thus a cleaner environment, with no downgrades or OTP required.
Currently, several custom firmwares for the Nintendo Switch console exist: Atmosphère, ReiNX and SX OS.
It leverages the Recovery Mode (RCM) of the Switch unit in order to push unsigned/unverified payloads,[9] in turn granting the user access to arbitrary code execution.
This vulnerability has been further leveraged by users within the Switch hacking scene to reverse-engineer the firmware, leading to two other notable exploits: Nereba and Caffeine.
While they cannot be modded by normal means ("softmodding"), a modchip can be soldered onto where the Switch's USB-C port would be after it is removed ("hardmodding"), thus circumventing the need to enter into RCM mode.
However, since about 2015[14] several manufacturers, including Motorola,[15] OnePlus,[16] Google[17] Xiaomi, and Sony[18] support unlocking the bootloader (except on models that are locked by some carriers).
Various other devices, such as digital cameras, wireless routers and smart TVs, may also run custom firmware.