technology

After MuscleNerd has declared about the new amazing Redsn0w jailbreak features, he has been asked about the downgrade for 6.15.00 baseband on iPhone 3GS and 3G after using ultrasn0w, he points that the work on the downgrade issue won't start only after the release of iPhone 4 baseband 2.10.04 unlock which expected to see the light in less than a month.

Fammbizz asking MuscleNerd: when is ur bb downgrade comin out for 6.15.00
MuscleNerd replying: TBH (to be honest), that won't be looked into until after i4 unlock

Many of users who unlock their devices using ultrasn0w 1.2 noted problems with their GPS, so we expect that downgrade will fix this bug, moreover, there is speculation about the possibility to downgrade the baseband to unlockable one which will be compatible with the old version of ultrasn0w. Stay tuned

Here's a bit of good news for who suffered from the new unlockable baseband 6.15.00 on iPhone 3GS and 3G. Most of the unlockers who unlocked their devices with ultrasn0w 1.2 can't restore to any stock firmware above 4.1, it only can be restored to a custom firmware, moreover, ultrasn0w 1.2 caused a loss of GPS. Let's check out the new progress regarding downgrade 06.15.00 baseband.

Lezanz: what about GPS issue? Any progress?

Musclenerd: sorry still collecting data on that. But also working on a bb downgrade (!) method for those with unlockable bb

MuscleNerd has confirmed in a tweet that he is working on a new method to downgrade baseband 6.15.00 to lower versions, which will be unlockable and to fix the GPS issue. Till now we didn't catch more details, but of course will let you know once we catch more, stay tuned.

It was possible that you have the curiosity to experiment iOS 4.2.1 GM new features which was released yesterday to iPhone 4, 3GS, 3G, iPod touch 4G, 3G, 2G and iPad, if you still didn't, you can download and jailbreak it now from here. You will note that Cydia still have some issues, the matter which make jailbreak pointless for many.


Moreover the new iOS 4.2.1 GM build has a new baseband version which puts a lot of doubts around the upcoming unlock. Therefore I prepared the downgrade guide from iOS 4.2.1 GM to iOS 4.1, 4.0.2, 4.0.1 or lower.
STEP 1: Download iOS 4.1 or older firmwares for iPhone or iPod Touch.

STEP 2: Put your iPhone in DFU Mode by following this steps,

• Connect your iPhone to your computer.
• Turn iPhone off.
• Start iTunes
• Hold Power and Home buttons together for 10 seconds or so.
• Release Power button but keep holding the Home button until your computer recognizes a new USB device.
• iTunes will now recognize your iPad.

STEP 3: If you are on iPhone 3G or iPod touch 2G (non-MC model) bypass this step. This step is about adding Saurik’s Server address to your system hosts file. This trick make iTunes thinks it is talking to Apple, while it is talking to Cydia while the restoring process.

• Locate "C:\Windows\System32\drivers\etc\" for Windows and "/etc/" directory for Mac, then locate “hosts” file andOpen it in Notepad (for Windows) or TextEdit (for Mac OS X) and add this at the bottom of the file.

74.208.105.171 gs.apple.com

At last it will be like that, then save it

STEP 4: Now, You will have to restore your iDevice to iOS 4.1, 4.0.2 or 4.0.1  by clicking on the iPhone icon on the left sidebar of iTunes then hold left “alt” button on Mac (“Shift” button on Windows) on the keyboard and then click on “Restore” then release the alt button, Now Select the iOS 4.1, 4.0.2 or 4.0.1 ipsw file you have already downloaded in Step 1 and let iTunes do some automated Steps.
STEP 5: You will need to exit recovery mode, so download TinyUmbrella (Windows / Mac). Run it and the click on “Exit Recovery” button. Your device will now restart normally.

Now you got back to iOS 4.1, 4.0.2 or 4.0.1 and you can jailbreak your iPhone using our guide posted here.