Unlaunch is the first ever released bootcode exploit for DSi consoles. It allows running homebrew with fully unlocked SCFG_EXT, loading DSiWare from the SD card, loading out of region carts and blocked flashcards, protects against most bricks, and more. Developed by Nocash it was first released on August 17th, 2017 and last updated on August 27th, 2019.
Some of Unlaunch's features have proven unpopular and community-made patches have been made to alter them. These are the background images shown in the menu and its patches to the DSi Menu. These patches are applied when installing Unlaunch using TWiLight Menu++ with the appropriate settings enabled.
DSi Menu Patches
The most controversial aspect of Unlaunch is that it applies several patches to the Nintendo DSi Menu with no option to disable them. These include several which are generally desired such as removing flashcard blocks and RSA checks, however it also removes the Health and Safety splash screen and all sound from the DSi Menu.
When Unlaunch is installed using TWiLight Menu++ it will apply patches to the Unlaunch installer based on TWiLight Menu++'s "Launcher Patches" setting. This setting has three options: "Full" which does not patch the Unlaunch installer at all so all patches apply, "Default" which removes the splash/sound patches while leaving the rest, and "None" which makes it so that Unlaunch does not patch the DSi Menu at all.
On consoles capable of running homebrew with access to NAND, installing Unlaunch is very simple. The Unlaunch installer simply needs to be run and the "INSTALL NOW" option selected. It is recommended to use TWiLight Menu++ to run the Unlaunch installer as it includes patches to change the background image and remove the unpopular splash screen and sound patches Unlaunch normally applies to the DSi Menu.
Since version 1.8 Unlaunch has included a file browser which, with default settings, is shown on turning on your console. This file browser allows for running any DSiWare or modern homebrew application from your NAND or SD card as well as the Slot-1 Game Card. It is also allows setting any DSiWare or modern homebrew to four hotkeys, in addition to when no button is pressed, which will load that application on turning on your console instead of Unlaunch's file menu. Unlaunch's file menu is set to always open when the console is turned on holding A and B, which cannot be changed.