Very soon TinyPwn will allow you to create custom firmware.
Hello iPhone users! The creator of the wonderful Tinyumbrella says he's working on a program to create custom firmware, similar to Sn0wbreeze and Pwnage Tool, and it will be available for Mac, Windows, and Linux. No release date has been announced yet.
As you know, a custom firmware is an iOS with an integrated jailbreak that can also perform activation on illegal iPhones that are in emergency call mode. Until now, it was only possible to create them using SnowBreeze on Windows or PwnageTool on Mac, and this new program will allow this procedure to be performed on Linux as well, a very good option that we will probably have in our hands soon, in addition to some other features that will be integrated although they have not been revealed at the moment.