So recently i found myself struggling with an iphone 4 that just would not restore in itunes. No matter how many tries or how much googling i did, i found nothing. However i did end up finding a solution and figured i'd make a tutorial :)
STEP 1: you're gonna want to go to http://ih8sn0w.com/ and download the newest version of sn0wbreeze. (note it is a windows only program)
STEP 2: Open sn0wbreeze and create a custom ipsw for your device and the newest version of IOS.
This will prevent updating the basband. Error -1 is a result of a corrupt basband chip. However the phone does work just fine.
STEP 3: Run iReb in Sn0wbreeze to get your phone into pwned dfu mode. This will allow the phone to restore to the ipsw you created.
STEP 4: Open itunes and hold shift, then press restore and select the ipsw you created.
STEP 5: Your phone will look like this when restoring. Just sit back and relax now. You have successfully fixed error -1! :D