Ok,
I tried to follow this guide to downgrade to 1.1.4:

MacCiti | iRevolution

Instead of using ziphone (last point) I updated to 3.0 with iTunes 8.2 and then jailbroke with redsnow.

When bootneuter start to work it says that my bootloaders 3.9 and 4.6 are already installed and it will only flash my baseband.

After this my iphone doesn't work (phone part).

Any suggestion?