Dop-IOS lets you download and install any IOS from Nintendo servers. You can also apply the trucha bug to them.

Changelog:

Version 4
* It seems that ES_Identify patch can be buggy in other IOS than 36. So now Dop-IOS is able to apply this patch only on IOS36.
* SD files now are stored on sd:/00000001 and they can be used in other applications.
* Now Dop-IOS v4 shows your installed IOS versions!

Version 3
* Dop-IOS v3 now patches ES_Identify too! Thanks to Scarfish code.
* Now any downloaded IOS is copied to SD. Next time Dop-IOS will use these files instead of downloading them again. This will be helpful to users without internet.
* SD backup code taken from Hermes' cIOS installer.
* IOS60 and IOS61 cannot be installed as older versions in order to avoid confusions.

version 2
* Dop-IOS v2 now can download also older versions of any IOS.
* A button - Downloads latest version in Nintendo servers of selected IOS
* Minus button - Downloads older version (with trucha bug if possible) of selected IOS
* It also has a protection and it doesn't allow to install latest stub IOSes: 4, 10, 11, 16, 20, 30, 50 and 51. You can still install older versions if you want (and if possible), but any update (internet or disc) will replace them with the unused stubs.