iPhone 4 Custom Restore Firmware 4.2.1 with 01.59.00 Baseband

How To Update iPhone 4 on 4.2.1 Firmware using Custom Restore with 01.59.00 Baseband. If you are having iPhone 4 running on Firmware 4.2.1 and having modem firmware version you are eligible to unlock your iPhone 4 career after reading this article. I was getting Error (21) or (1600) when restoring iPhone.

Actually when i was trying to custom restore my iPhone 4 to firmware 4.2.1 i was getting above Error (21) and (1600). Unforunately when I load the phone into iTunes, it gives me the error code (21) when in Recovery Mode and the error code (1600) when in DFU Mode. So to resolve this problem you must have following things ready to start with and successfully custom restore your iPhone 4.

Note: These are the instructions on how to restore or update iPhone 4 on iOS 4.2.1 by preserving the baseband to 01.59.00 using Custom Firmware. Those of you who have already upgraded to 4.1 and 4.2.1 and are on their respective Modem Firmware (02.10.04, 03.10.01) this is strictly NOT for you. wait for the unlock to come.

Steps to iPhone 4 Custom Restore Firmware 4.2.1 on Baseband 01.59.00

Step 1: Download all the prerequisite softwares before moving to step 2.

Download the following files for Custom Firmware of iOS 4.2.1 (iPhone 4):

http://www.filesonic.com/file/921382094/iPhone3,1_4.2.1_8C148_Custom_Restore.part1.rar
http://www.filesonic.com/file/921382184/iPhone3,1_4.2.1_8C148_Custom_Restore.part2.rar
http://www.filesonic.com/file/921376274/iPhone3,1_4.2.1_8C148_Custom_Restore.part3.rar
http://www.filesonic.com/file/921382074/iPhone3,1_4.2.1_8C148_Custom_Restore.part4.rar
http://www.filesonic.com/file/921382204/iPhone3,1_4.2.1_8C148_Custom_Restore.part5.rar
http://www.filesonic.com/file/921382114/iPhone3,1_4.2.1_8C148_Custom_Restore.part6.rar
http://www.filesonic.com/file/921382064/iPhone3,1_4.2.1_8C148_Custom_Restore.part7.rar

and

Download Redsn0w 0.9.6rc14 for Windows from here: http://www.filesonic.com/file/956943031/redsn0w_win_0.9.6rc14.zip

and

Get Stock/Original iOS 4.2.1 Firmware (iPhone 4) from: http://www.filesonic.com/file/921549611/iPhone3,1_4.2.1_8C148_Restore.ipsw

Step 2: Connect your phone with your computer and switch it off.

Step 3: Open Redsn0w and browse original 4.2.1 firmware.

Step 4: if your phone has new bootrom version then select Yes and click on the next button.

Step 5: Select “Just Enter Pwned DFU Mode Right Now”

Step 6: click on the next button and follow the on-screen instructions to put your device in DFU mode.

Step 7: open iTunes. on Summary tab, hold shift key on your keyboard and click on the Restore button. A dialog box will appear , asking you to select .ipsw firmware. select custom 4.2.1 firmware and click Open.

Step 8: wait for 5-10 minutes for phone to restore.

Step 9: Disconnect your phone once the restore is complete and connect it again and launch Redsn0w.

Step 10: Browse original firmware on Redsn0w and select “Yes” if your phone is a new bootrom model and click on next.

Step 11: Select only “Install Cydia” as option and click on the next button.

Step 12: follow the instructions and put your iPhone in DFU mode.

Step 13: if your phone stuck, re-run Redsn0w and select only “just boot tether right now” option and click on next button.

Step 14: Open Cydia and add repo666.ultrasn0w.com/ to install Ultrasn0w package so that you could unlock your phone.

You now have a fully jailbreak and unlocked iOS 4.2.1 on iPhone 4 with 01.59.00 baseband.