Softmod

A softmod is a method of using software to modify the intended behavior of hardware, such as video cards, sound cards, or game consoles in a way that can overcome restrictions of the firmware, or install custom firmware.
Video card softmods.
Video cards that can be modified using software to faster versions (without regard to clock speed) usually contain mostly the same hardware. Softmodding a card should not include changing the video card's BIOS, as that is a BIOS flash. Currently only four softmods are known, a Radeon 9500 NP to a 9500 Pro (128 bit) or 9700 (256 bit), a Radeon 9800SE (with 256-bit L-shaped memory layout on the PCB) to a Radeon 9800 Pro, a GeForce 6200 to a 6600, and a GeForce 6800NU to a 6800GT. The act of a softmod usually enables pixel rendering pipelines, though may also include other enhancements. A softmodded card may not always reach the same performance as the real card it has been changed to, but the difference should be very little; and generally not noticeable. The softmodding is not guaranteed to always work; sometimes the
pipelines have been disabled for a reason, e.g., a defect that produces artifacts when enabled.
Softmods for Xbox.
Softmod is also a term used to refer to modifying an Xbox without the use of a mod chip.
Softmods for Xbox used to include a font exploit installed through exploits in savegame code for "MechAssault", "Splinter Cell", "007: Agent Under Fire", and "Tony Hawk's Pro Skater 4". Usage of the "Splinter Cell" or "Tony Hawk's Pro Skater 4" disc is generally recommended as any version of the game will run the exploit, whereas certain production runs of Mechassault and "Agent Under Fire" are needed to use the exploit. Originally, via a piece of software called "MechInstaller" created by members of the Xbox-linux team, an additional option could be added to the Xbox Dashboard for booting Linux. The Font-hack works by exploiting a buffer underflow in the Xbox font loader which is part of the dashboard. Unfortunately, since the Xbox requires the clock to be valid and the dashboard itself is where you set the clock there is problem if the RTC backup capacitor discharges. The Xbox will detect that the clock isn't set and therefore force the dashboard to be loaded which then promptly reboots due to the buffer overflow exploit. Upon restarting, the Xbox detects the clock is invalid and the process repeats. This became known as the infamous "clockloop".
Softmod for Xbox 360.
There is no whole-system (that will allow full root access and installing homebrew) softmod for Xbox 360 consoles. However, ways were found to modify the firmware of the DVD drive of the console. This allows the system to play games from "backup" (non-original) game discs. This requires opening of the console but no additional hardware such as a modchip is permanently installed into the system. Microsoft responded by introducing console ban system. If the data stream from the DVD drive indicated signs of unauthorized use, Microsoft would permanently ban the console from using Xbox Live service. The ban never expires and can only be fixed by purchasing another console. Other measures, such as introducing new hardware revisions to prevent modifications and checking/updating the drive firmware during dashboard updates, have been made too.
Softmods for PlayStation Portable.
Much like the Xbox, it is possible to softmod almost any PSP. Using various exploits (such as the TIFF exploit or specially crafted savegames from games such as "", "Lumines", and later "GripShift") or original unprotected firmware, the user can run a modified version of the PSPs updater, that will install custom firmware. This newer firmware allows the booting of ISOs, as well as running unauthorized (homebrew) code. A popular way of running homebrew code to softmod the PSP is by using the Infinity method.
Softmods for Wii.
Wii softmodding is also closely related to the methods used to softmod Xboxes and PSPs. The first known method of loading unsigned code on a Wii (without a hardware mod) is known as the Twilight hack. This allowed users to run unsigned .dol/.elf files. The exploit was superseded by the development of Bannerbomb, which allows a user to run unsigned code on the console without relying on an exploit within a game. Bannerbomb works by using a malformed banner to inject a loader program into the Wii Menu program in memory. As the Wii Menu crashes, an unsigned executable is executed. Bannerbomb was superseded by Letterbomb, which uses a glitch in the Wii Message Board to crash the Wii Menu and load the .dol/elf file, allowing the user to install the Homebrew Channel.
These types of exploits have enabled the development and use of third-party homebrew applications, such as the Homebrew Channel, third-party games, media players, and many others. It can also be used to launch game backups, and opened the door to videogame copyright infringement. The Wii homebrew community generally discourages the use of the term "softmod" to refer to Wii homebrew in general, as it is considered to have negative connotations due to its association with copyright violation. As hardware modifications do not help the use of third-party software due to the console's security architecture, software modification is implied whenever homebrew software is in use. The term is therefore used to refer to software modifications that perform the same function as existing hardware modifications, that is, those that enable the use of copied games.
Softmods for PlayStation 2.
The PlayStation 2 has various methods of achieving a softmod.
Disc swapping was used early on to bypass the Playstation 2 copy protection, by taking advantage of certain trigger discs such as "007: Agent Under Fire" or Swap Magic, homebrew could be loaded. This was done by inserting the trigger disc, blocking the lid open sensor then hotswapping with a homebrew disc. Although difficult to execute correctly, the universality of the method was often used in order to softmod.
One of the earliest softmods developed - the Independence Exploit - allows the PlayStation 2 to run homebrew by exploiting a buffer overflow in the BIOS code responsible for loading original PlayStation games. This method, however, only works on models V10 and lower, excluding the PlayStation 2 slim, while still requiring a disc to be burned.
FreeMcBoot is an exploit that works on all models except the SCPH-9000x series with BIOS v2.30 and up. It requires no trigger disc and is able to directly load ELFs from the memory card.
HD Loader is an exploit for PS2 models with the hard drive peripheral. 
FreeDVDBoot is an exploit discovered in 2020 that requires burning a disc image loaded with a payload onto a DVD-R. It is compatible with a range of Playstation 2 models and works by exploiting a buffer overflow in the PS2's DVD video functionality.
Nintendo 3DS Modding.
The Nintendo 3DS has become one of the most popular console platforms for modding, as the procedure requires very little other than the 3DS itself, and is relatively simple for the latest firmware (version 11.13.0 as of July 2020) and below, using the "unSAFEmode" method. Other methods use either a 3rd party "flashcard" with an "NTR Boot" payload, or more difficult techniques, such as a NAND memory hardmod or DsiWare injection system transfer exploit. The most well developed and commonly used Custom Firmware (CFW) is known as Luma3DS. It contains features such as EmuNAND, A.K.A. NAND redirection, running non-system menu payloads on boot, and installing Homebrew titles to the main menu. A popular homebrew app used for piracy, known as "Freeshop", was shut down by Nintendo with system update 11.8 by requiring a title key authorization on the Eshop download servers, thus making all NUS downloaders for the 3ds to no longer function.
Computer DVD drives.
Some DVD drives, such as those made by Lite-on, can be softmodded to ignore region coding, allow clearing of the drive's learned media calibration data, and enable DVD+R to DVD-ROM book type coding that is persistent across reboots. This is distinct from crossflashing the drive or installing unofficial firmware, and does not modify the drive's firmware.