It's funny, I've read a bunch of pages on restoring firmware that Apple is no longer signing. Some of them go on and on like theres no tomorrow, with steps and procedures. Some recommend downloading tinyumbrela and going through that whole process. All of them recommended putting your phone in DFU mode before proceeding. I decided to put a fresh copy of 4.0.1 on my phone and re jailbreak because my phone had slowed down due to trying out tons of random stuff. So when I went to restore I thought I was in for some work. After really reading some of these pages, I thought "why the hell would you have to go through all this trouble? As long as iTunes thinks it got its signature, it should work as normal". Well I was right. All I did was add that one line to the hosts file, using notepad. I then opened iTunes, held shift, clicked restore, clicked the 4.0.1 firmware and...that was it. iTunes verified the software, installed it, re-synced, and boom done. No DFU mode, no downloading my SHSH's, no kicking out of recovery mode. Just let iTunes do it's thing. Sometimes I wonder why people insist on making things complicated.