Hey guys i just noticed that you can still go back to 4.0.1 just download the 4.0.1 firmware from the net and then go to itunes and press shift key and update at the same time and that will do it ....it works tested by me just now ...this only may last for today or tomorrow so do it fast.......enjoy.
This is because Cydia has your SHSH files on it's server. This isn't possible without Cydia so make sure you back up your SHSH using TinyUmbrella or choose the "Make my life easier" on the home page of Cydia when you first Jailbreak.
I do not think it is Cydia (unless they changed the host file to point to Cydia's server). More than likely, when they tried to go back to 4.0.1 it was still being signed by Apple. Not sure if this is still the case as of now... If it is, get your SHSH files now!
Hi I have just bought an iphone 3gs from ebay,
it was on the 3.1.2, and it is not jailbreak before, i tried to update to the 4.0.1 using itunes and I was successful, thus it is not cydia which is responsible for the downgrade at least until now.
so you can do it till that time it is 5:00pm in MI