Rogero himself never called the version v4, It's just a test CFW he made for people to test and one of the testers leaked it and trolled people, calling it brick free.
Yesterday i install Rogero 4.21 v1 on a ps3 slim cech-2501a, the one that came with uncharted 2, Karate Kid Blu-Ray + Pixel Junk Shooter, this console was hardware downgraded 6 month a go, i follow the steps on the tutorial and it worked. today when i get home i will resign my psn downloads and try MLB 2012.