Hello Friends, This is my first post here, i have found these forums to be extremely informational and helpful. I Have a Jail-broken iPhone 5 Running 6.1 Everything was fine, until this morning. I woke up and saw that there was no carrier signal, so i rebooted the device. This is when it all started. My iPhone went in to a boot loop and it started flashing the apple logo over and over again. I was able to enter the recovery mode (connected to PC while keeping the home button pressed) and the iTunes logo appeared. Tunes displayed a message that the phone needs to be restored and it started downloading the latest firmware (6.1.3). I knew i will loose the jailbreak but i wanted to get my phone up and running so i went with it. Once the file was downloaded, it started the restore process, verified it with apple and once the phone rebooted it gave me an unknown error 21. I googled about it and most of the results pointed towards putting the device into DFU mode. Now in the DFU mode, i have encountered 2 different scenarios. A. If I enter the DFU mode from the recovery screen (the iPhone is displaying iTunes Logo) iTunes start the recovery process, validates everything and during the process the iPhone reboots, the recovery screen(iTunes logo) comes and I get the error 21. B. If i enter the DFU mode from the apple loop, iTunes start the restore process, the iPhone reboots. after the reboot, the phone goes back to the apple logo loop and the iTunes displays that it is validating the restore for a long time and then give me the 1602 error. I also read somewhere that the Error has some thing to do with Tiny umbrella. I have modified the setting in tiny umbrella and modified the hosts fine but nothing seems to be working. As a last resort i shifted to a different computer(i have never used any iPhone with it) installed the latest iTunes but i get the same results. Then i read somewhere that disconnecting and reconnecting the battery also fixes it. I am not keen to do that i have no experience with hardware and i am not sure i will be able to do it. Please help me, this is my first iPhone and i have spent all my day looking for a solution but i cant seem to fine one. If i cant fix it and have to give it in for repairs, will Apple find it that my phone was jail-broken. If yes, they might not fix it or charge me a fortune to fix it. Thanks in advance, Shamps.