Well I couldn’t leave it like that so I was playing with that today more and I managed to install the whited00r firmware, thanks to this detail description.
Unfortunately it’s not iOS 6. It’s iOS 3.1.3 with some of the features of iOS 6, but not compatible. Means you can’t download newer apps from the Apple store. Actually I tried about 5 apps (Google maps, etc..) and I didn’t found any that can be downloaded :(.