How to: Upgrade iPhone 3GS 4.2.1 (BB 05.13.04) Using Custom Firmware [Guide]

by this you don't Have to worry about future upgrade. Because once you upgrade your baseband to 6.15.00 you cannot update your phone with apple original firmware in future.

Before you Start this procedure. Make sure you have BB 05.13.04.....or below...

See the image...

Tools needed.....

1 . Custom firmware for iphone 3GS 4.2.1...MEGAUPLOAD - The leading online storage and file delivery service

2. Redsnow - http://sites.google.com/a/iphone-dev...edirects=0&d=1

3. Apple original firmware 4.2.1 for 3GS - http://appldnld.apple.com/iPhone4/06...a_Restore.ipsw

1. Connect your phone with PC and switch off...

2. Open redsnow and choose Original firmware...

3. If you have newboot just press "yes"

4. now click "Next"

5. Choose "Just Enter pwned DFU mode right now"

6 now click "Next" again "Next" and follow the screen....

After that open itunes and press "Shift + Restore" and choose custom firmware 4.2.1...

it will finish very quickly ......

Once you update you firmware....follow this...

1. Connect your phone with PC and switch off...

2. Open redsnow and choose Original firmware...

3. If you have newboot just press "yes"

4. now click "Next"

5. Choose Only "Install Cydia"

6. now click "Next" again "Next" and follow the screen....

If you r getting White Cydia Icon just switch of your phone and open redsnow choose Stock firmware 4.2.1 and choose the option "Just boot tethered right now" and click "next" again "next" then follow the screen...then you will see the cydia...

Finally you can see your phones is with your old Baseband. now just you can install the ultrasnow 1.2 from Cydia adding this link "ultrasn0w.com"For more news coverage, you can follow us on Twitter or become a fan on our Facebook page, we will keep you updated with posts over the web.