Friends, I was trying to upgrade unsuccessfully to 2.0 from 1.1.4 several times using my laptop, which has Windows XP SP2. I used the procedure step by step, but it was not working, since the custom restore file was not being created.
Then I used my home computer, which has Windows Vista, follow the procedure (I had to try several times to put the iphone in DFU mode), but at the end, Winpwn did its work.
One tip: when BootNeuter was finishing, a message popup at the end saying that something was failed, but it was so fast that I was not able to read the whole sentence. However, the process completed successfully, even with that horrible message.
I got signal, wifi, and I'm actually testing all other features of the iphone to verify if it works properly. The first thing I tried was BootNeuter: it made my iphone to freeze, but I restarted and everything appears to be OK. I'm saying this in this way because I'm just doing it right now. In fact I have set my Exchange account, and it is working nicely.
I will report any issue I would find (if I find it), but I don't think I will.
Thank you very much to the team that worked very hard in the Winpwn. It's simply excellent.