Downgrading the Baseband

Using the secpack from the new baseband, it is now possible to downgrade the baseband, effectively allowing a complete downgrade from 1.1.1 to 1.0.2. See below for instructions on baseband downgrading. However, its important to note, downgrading the baseband can cause your iPhone to go into an irreparable state, if something goes wrong along the way. It’s recommended that you don’t follow the tutorial, instead, wait for a safer solution.
downgrading the baseband
Please note, downgrading the baseband does not reset the NCK count or completely reverse changes made by HW unlocking/iUnlock/AnySIM/etc. If you keep on upgrading or downgrading, you will get to a point where unlocking is not possible.
It is still safe to downgrade the O/S from 1.1.1 to 1.0.2
Note: This processs seems to works regardless of the order of events, you may downgrade the O/S from 1.1.1 to 1.0.2 first, later downgrade the baseband and then activate the new Sim card. Note: If your ipod goes into an “irreparable state” watch it when you run apptapp if it goes to the home screen for just a moment, unplug it and it will be able to used again Note: There are TWO RESTORE MODS!!! one with the plug and itunes logo and one with the yellow sign,….You want the yellowsign….
[edit] Method A (Instructions)

(from hackint0sh.org)
Here are the steps:
Make sure you have a copy of the 1.0.2 firmware handy and decrypted
Reboot iPhone holding top (power) and home buttons *BUT* release the top button exactly 10 seconds (I recommend using a stopwatch) into it
The iPhone screen will appear to be off, but start iTunes (latest version worked for me on the Mac)
Option+Click restore and select the 1.0.2 firmware ipsw
The phone will restart and error( 1013 ) out at the end, this is expected
Shutdown iTunes
Launch the latest iNDpendence
Jailbreak the phone using a decrypted 1.0.2 (it will flash all sorts of error, but stick with it)
Activate the phone
It will show the SIM error but you should be able to get back in
AT&T Users: Reset your iPhone before you start using your phone again. Failure to do so may result in you being charged for your “free services.”
Please note: The Sync cable and itunes logo is the new firmware restore screen. The yellow triangle is the old restore screen.
SUGGESTION FOR WINDOWS USERS Having difficulty entering DFU mode:
(Guide from MJFlash)
Hold down the Power and Home buttons until you hear the disconnect tone (that is the two tone sequence indicating that a USB device has disconnected). Then release the power button and continue holding the home button until you hear a quick pair of connect and disconnect tones, then release the home button.
I installed AppTapp afterwards along with the BSD subsystem and SSH, all working over wireless only. Now we need to see if we can get bbupdate to play ball.
Note: I didn’t need to have the firmware decrypted in any way for this to work (just unzipped). –0p
==successfully complete. Keep rerunning AppTap if it doesn’t work the first time – it may take a few tries.
At this point you will have a jailbroken iPhone that still needs to be activated (as usual). Google is your friend.
AT&T Users: Reset your iPhone before you start using your phone again. Failure to do so may result in you being charged for your “free services.”

Please note: The Sync cable and itunes logo is the new firmware restore screen. The yellow triangle is the old restore screen.
Error: The iphone “xxx” could not be restored. An unknown error occured (1).
Some user experienced the above error message and iTunes won’t update the iphone firmware. Anyone know how to solve this issue?
This problem is 2 fold… people goto the restore screen instead of letting the blank screen load on the iPhone. Also, I encountered this error on Vista on 3 separate machines. Using an XP box fixed this problem for me.
@@@ For me, the solution to “An unknown error occured (1)” when trying to downgrade to 1.0.2 was to downgrade to 1.0.1 then upgrade to 1.0.2 – Blatwurst @@@
I got the activation screen after restoring and not the “Please Connect to iTunes” message (in fact if I got this screen AppTapp would not work) but got the Activation screen instead. If, and only if (trust me I have tried some 20+ times now) I get the Activation screen, I can successfully run AppTapp. Otherwise, if I got the Yellow Triangle / “Please Connect to iTunes”, I would have to do a Shift+Restore to 1.0.2 and start over again until I got the Activation screen. This is a subtle but important difference from the procedure and expectations laid out above, other than that everything else was the same.
I had the same error message. I had to update the firmware for my Mac Pro. Then I did the steps above and it worked perfectly. The only thin I can’t do is use my T-mobile sim anymore. Everything else works great. (youtube, wifi, etc.)
The Error on Vista is down to timing, using a stop watch I held in the power and home buttons for precisely ten seconds, I then released the power button but kept the home button depressed for precisely another 10 seconds then released it, a few seconds later Vista appeared with the “Detected new hardware message” the the iTunes restore worked. If you hold in the home button too long it will fail. Also this was on an OOTB 1.1.1 iPhone.
I had this error, too. I reinstalled iTunes (now at 7.4.3), restored to 1.1.1, and then restored to 1.0.2 as above.
I had the same error, I tried in 3 separates WinXP SP2 machines and 2 separates Mac OS X machines with different versions of iTunes(7.3.0.5, 7.3.2.6, 7.4.3) with the same iPhone(Test Point unlocked on 1.0.2), always I found the same error, i didn’t use the stopwatch I always wait for the restore screen pressing both buttons, I’m going to try with the stopwatch to confirm. If anyone have a tip for me please let me know.
The stopwatch is a must! It worked for me. Exact 10 sec power/home, then release power and 10 sec home button. But after downgrade, I’m trapped in the restore mode. I run AppTapp and although it shows as completed, iphone keeps in restore mode. I’ve tried in a winxp with 7.3.0.54 and in a wista with 7.4.3.1 machines, but nothing. Any suggestions? Thanks!
Definately a time thing! You have to make it So the Connect to iTunes symbol DOES NOT pop up!
I figured out a way with the force restore. While the iPhone is connected to the computer and with iTunes open, Hold the Home and Power button for 10 seconds approcimately. Once the “USB & iTunes logo” screen disappears, let go of the Power button but continue holding down the Home button. The screen remains black, but iTunes will detect the iPhone in recovery mode in +sometime. Now go as usual and restore the iPhone to 1.0.2 by holding down Shift+ Restore (on Windows). Worked for me perfectly.
Yes! I was getting error 1 and finally i tried teh stop watch method and it works! It is 100%! This way the restore works fine! Great work!
If your iPhone just boots to “Please connect to iTunes” all the time This is an issue that I had. What you need to do depends on your operating system.
Windows: – Download iBrickr and extract it somewhere. – Open a command line and cd to the folder you extracted iBrickr to. – Run iphoneinterface from the command line. – You should see an r_recovery prompt. – Type “setenv auto-boot true” and hit enter. – Type “saveenv” and hit enter. – Type “fsboot” and hit enter. – Your phone will boot properly.
Mac: – Download iPHUC and run it. – You should get a recovery mode prompt. – Type “cmd setenv auto-boot true” and hit enter. – Type “cmd saveenv” and hit enter. – Type “cmd fsboot” and hit enter. – Your phone will boot properly.
I really don’t know if that is the reason. I finally handled to resolve the issue with the correct version of AppTapp (took it from here–direct link to Windows executable)
[edit] Method C (Easiest Instructions)

Guaranteed to work with iTunes 7.3.2. Apple didn’t think of everything (J).

NOTE: I wrote a more visual tutorial based on this Method. It outlines some things that Method C missed for Windows. You can read it at this link. This link is for Windows users.*

Confirmed working with a locked iPhone that had been upgraded to 1.1.1. Downgrade using these instructions was successful. Phone is activated and all apps and 3rd-party software working.
NOTE: You must delete the 7.4 version of iTunes before you install 7.3. Go to Finder and search for iTunes and then delete all associated software, but make sure you don’t touch the file where your music is stored!!!! Move that to the side so you can add to iTunes 7.3
Install iTunes 7.3.2, which you can download from the links below.
Download the 1.0.2 iPhone restore file if you don’t have it already.
When you dock the iPhone and open iTunes, you will get an error saying this iPhone requires iTunes 7.4 or later. Just click OK. (The phone will NOT show in the devices column.)
Keeping your iPhone docked:
Slide to unlock
Hold down home button and power button for about 10 seconds or until the screen goes black.
Release the power button but continue holding the home button.
After about 10 seconds the computer will detect the iPhone in restore mode, and iTunes should tell you that the phone needs to be restored.
Shift + Click Restore (Windows) or Option + Click Restore (Mac), then point to the file below (use .dmg file in download file).
Use AppTap Installer you will be back to normal with EDGE and Wi-Fi support.

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