On March 6, 2011

Also read: Top 10 Must Have Cydia Tweaks for iPhone, iPad, iPod touch

iReb will put your iPhone (also other iDevices) into a pwned (jailbreakable) state so that you can upload custom firmware to it.
It can be used to fix unknown error 1600, 1601, 1602, 1603, 1604, etc.

iReb RC4

Download iREB RC4:


This compressed zip file contains iREB-r4.exe