Don’t post, if you don’t know! The entry in the host file is to preventing iTunes from connecting to gs.apple.com and redirecting it to the IP 74.208.105.171. This is just the trick to get a allowance from iTunes to install “not eligible” firmware.

Use this value in the HOSTS file: 74.208.105.171 gs.apple.com – some videos and instructions mistakenly give you this: 74.208.105.172 gs.apple.com

Use DFU mode – NOT recovery mode. If you see the happy cable coming up from the bottom of your screen to plug into iTunes logo then NO, YOU ARE NOT IN THE RIGHT MODE. In DFU mode the screen is completely black. If you don’t know the difference might I suggest a new tool known as Google?

OK, the HOSTS file thing is confusing to many people (based on comments on like 50 sites). I understand not everyone is an I.T. geek, so I will explain this. iTunes verifies that your phone can be restored with the version you are trying to use by contacting a particular server at Apple (named “gs” in this case). When iTunes goes out to get approval it looks up the IP (that is the actual address) of the server, gs.apple.com (gs is the hostname, apple.com is the domain). All workstations will look at their local HOSTS and on Windows LMHOSTS files first – then go to DNS servers next. By adding this one line you are basically tricking your machine to go to the Cydia server instead of the GS server to check for the certificates/permission to perform the upgrade. There seems to be a lot of people with security concerns here – which begs the obvious question, “Why the hell are you jailbraking your phone with untrusted software in the first place?” If you trust enough to Jailbrake and put many, many piece of software from people all over the world (even some 12 year old in Russia) then changing one host value on your system is the absolute LEAST of your worries.

Make sure you are using iTunes 9 and the restore file: iPhone2,1_3.0_7A341_Restore.ipsw – I tried others and they did not work. If you Google this file name you get hundred of hits as to where to download it so there is no need for me to post that here.

OK…this is absolutely CRITICAL. In order for this to work AT ALL you had to have had an iPhone at 3.0.x, jailbroken, connected to Cydia and allowed it to copy your SHSH stuff. Jay only had this process up for a VERY short window. It has long since been shut down and if you didn’t do it at 3.0.x then it is pointless anyhow. You would know if your information is stored – you would have had to have allowed Cydia to extract it and every time you went to Cydia you would see a message that says This iPhone has an SHSH file at Cydia or something like that on the top of the screen. It you are not sure, then there is a 99.9% chance you did not have it and you just need to live with 3.1.x….deal.

Another thing that is mentioned in some of the tutorials – you WILL get an error (though there is some discrepancy as to which error) the first time you do this. After it fails, do it again. You will get an error again at the Restoring iPhone Firmware part after the recovery, but this time you have been downgraded. As per several tutorials and my experience it works the second time…sort of

After this your iPhone should be in a loop and only boot to Recovery Mode (cable/iTunes logo). There are two ways out of this – one, use iRecovery (again, Google is your friend) to get out of this, or just Jailbrake at this point – either works.

For far more information go here:
http://www.saurik.com/id/12

And remember to thank Jay every chance you get.

If you get help, please let me know.