I managed to downgrade my I.4s from iOS 6 to 5.1.1 this way:
on my PC i go to C:\Windows\System32\drivers\etc
opened file hosts as Notepad and edited # sign to every single line like this:
Code:
# Copyright (c) 1993-2009 Microsoft Corp.#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
# localhost name resolution is handled within DNS itself.
#127.0.0.1 localhost
#::1 localhost
# 127.0.0.1 gs.apple.com
#74.208.10.249 gs.apple.com
#127.0.0.1 gs.apple.com
Than I opened iTnunes and holding Shift on keyboard click on Check for Update
than select iOS 5.1.1 file for downgrade
thats all