Is it possible to upgrade from ios 4.3.5 to 5.0.1 even though the current version is 5.1? My iphone has ios version 4.3.5 (8L1). I want to jailbreak/unlock it. I see that the latest jailbreak is for version 5.0.1 (by redsn0w). Itunes only allows me to upgrade to the latest version which is 5.1. But if I do that the jailbreak would be undoable.

Is there a way to upgrade to 5.0.1?

If not, is there a jailbreak available for 4.3.5?
Actually, you don't even have to hunt it to a Bittorent. You can just download it from the Apple servers by visiting the RedMondPie website. Links are listed below the page.