How to : Update iPhone 4 to iOS 4.1 with Preserving Baseband 01.59.00

Yesterday we reported you that the new hacker guy Pod2g has found an exploit to jailbreak iOS 4.1 after releasing with few hours, but till now there is no news about the baseband exploit, so the dev team warnned the upgrade to iOS 4.1 as you may lose your unlock may be for ever. Fortunately Notcom, the guy behind Tiny Umbrella, with version version 4.1.3, he discovered a method to preserve your iOS 4.0.1 baseband 01.59.00 while updating to iOS 4.1 on iPhone 4.

Important note: Until there is a jailbreak available for iOS 4.1 on iPhone 4, you will not be able to use ultrasn0w, So proceed with caution and backup your SHSH blobs first, We are not responsible for any problem occured you your iPhone 4 device after this guide.

Step 1: Close iTunes or any other application.
Step 2: Launch Tiny Umbrella then connect your iPhone 4 (Download Tiny Umbrella)

Step 3: Hit the "Start TSS" Server button

Step 4: Now launch iTunes and restore to iOS 4.1, (Note: do "Restore" not "Update").
Step 5: Wait for iTunes to end up with "error 1004". This is normal and has to do with the baseband not being updated.
Step 6: Simply "Kick Device Out of Recovery".
That’s it. You’ve upgraded your iPhone 4 to iOS 4.1 with 1.59.00 baseband. [via ihackintosh]