Hey guys, So I generated a custom firmware for my iphone 4 on my friends mac using PwnageTool -- which created iPhone3,1_4.2.1_8C148_Custom_Restore.ipsw I didn't want to use PwnageTool to do the restore because my shsh files are stored on my windows machine. So I took the IPSW to my windows machine, fired up TSS Server, put my iphone in DFU mode (made sure screen is black), and when I do a Shift+restore, I get this error: The iPhone "iPhone" could not be restored. An unknown error occured (1600). Any ideas? Thanks!! EDIT: Just realized I'm running iTunes v.10.0.1. That could be the problem?