Updated : v1.1
Some users have reported that after installing firmware 1.1.4, the phone doesnt detect the SIM. In this case, the baseband has to be reverted back to the old one. So you have to download one more software called KiPhone and 2 extra steps have been added to show how its done i.e Step 5 and Step 6.

You might be wondering, why I am writing a tutorial about Downgrading an iPhone’s firmware, well 3 days back I got an iPhone 2G from a friend. It was running v2.0 firmware. Since v2.0 firmware doesn`t support the good’ol Installer (Installer : An application used to download and install a wide variety of applications packages hosted online. Something similar to Itunes App Store except this is free . Ofcourse data transmission charges are applicable as per your network), I decided to downgrade the firmware to 1.1.4 since there are lots of applications available for download on 1.1.4.

Anyways I decided to run a check on google to find the perfect method to downgrade the firmware and what results were quite disappointing. There were millions of methods and barely any of them worked. (I tried quite a few) So this tutorial is for people like me who wasted hours trying to downgrade their iPhone firmwares but don`t have a clue on how to go about it.

Warning : Vision Master Designs is not responsible, if in any way your phone gets damaged after following this tutorial/procedure. This procedure worked fine for me and so I am posting a simple workaround for people struggling to find a solution on downgrading their phones.
This Procedure is for the 1st generation iPhones

By the way, thanks to apple, your phone can always be restored via iTunes(in the locked state), if anything goes wrong. This Procedure works for both v2.0.0 and v2.0.1

If any queries, you can always post a comment. So read on !

First of, you require the following Softwares.

1. Apple iTunes 7.5 : Click Here for a direct Link from Apple
2. ZiPhone 3.0 : Used to Jailbreak,Unlock,Activate and downgrade baseband if necessary, with just a click of a button.
   Click Here to Download the Windows version
   Click Here to Download the MAC version
3. KiPhone : Download KiPhone to help you restore your iphone’s baseband version.
   For Windows – Click Here
   For Mac – Click Here
4. Firmware 1.1.4 : Click Here to download

Note : If you have any other version of iTunes installed i.e apart from 7.5, please uninstall it !! Even though you have the latest version of iTunes (i.e 7.7.1) please uninstall it and install iTunes 7.5. Also Delete the iTunes Library.itl located in My Documents -> My Music -> iTunes.
In Windows Vista C:\Users\username\Music\iTunes.

Step 1

Assuming you have installed iTunes 7.5 and rebooted your computer. Open up the taskmanager i.e Ctrl+Alt+Del and goto processes. End Task iTunesHelper.exe.

Step 2

Connect the iphone via the USB cable. See whether iTunes detects the iPhone. Either ways, whether it detects the phone or not, open up iTunes. Now you have to put your iPhone into DFU mode.

Step 2.1 – DFU MODE

This is very important. Please note that there are 2 modes in which your iPhone can be put on while restoring any firmware.

1. Recovery Mode : This is the mode where you see the cable connector with the itunes logo image on the iPhone. Your iPhone will display the following image on its screen.

   

2. DFU Mode : This mode is used while flashing your iPhone with a new firmware or a old firmware. It is independent of iTunes as well. Most people have the problem of entering into the DFU mode. The main way to distinguish between Recovery mode and the DFU mode is, from the screen of the iPhone.
   In DFU mode, the screen is completely blank unlike recovery mode.

   Method to get into DFU mode :

   1. Please first switch of your fone.
   2. See to your fone is connected to your computer. Start iTunes.
   3. Press the home button and the sleep/wake button together. Keep both of them pressed. Start counting till 10
   4. After you finish counting till 10, release from the sleep/wake button !! only the sleep/wake button. But please keep your home button still pressed !
   5. Keep the home button pressed till you see the following screen on your iTunes.

      

Step 3

Click OK. Now keep your “Shift” Key pressed and click on the Restore button. You`ll see that a browse window popped up. Select the iPhone1,1_1.1.4_4A102_Restore.ipsw which we downloaded.
Click on Ok ! You`ll see that the firmware file is being Extracted and Installed.
Finally during the Verification Stage, you will encounter an error. (Most probably 10xx error)

Note : As long is it is not a 16xx error, there is nothing to worry about. If you encounter any of the 16xx errors, then there is a 90% chance that you are not using the correct iTunes version.

Step 4

After you encounter the 10xx error, you will notice the screen of iPhone is that of the “Recovery Mode” i.e you`ll see the above Recovery mode image on the screen of your iPhone.
Provided you see this image on your iPhone, Restore the firmware again. !

Thats right, restore the firmware once again.

Keep the shift key pressed and then select the firmware file and restore AGAIN ! –> Very Important

Step 5

If you encounter the same error after the second restore, no problem. Quit iTunes.
Now you have the 1.1.4 firmware with the wrong baseband. To correct it, Open KiPhone. Please unzip all the files into a folder before starting Kiphone.
Run KiPhone with options
Debug Boot – CHECKED
iErase – CHECKED
downgrade – UNCHECKED

Step 6

Once you have performed the task with kiphone, run Itunes 7.5 again and restore the 1.1.4 firmware once again. Now the firmware with the correct baseband will be written. You may have to put your phone into recovery mode/DFU mode if its not being detected by iTunes. Finally to Unlock the iphone follow Step 7.

Step 7

Open up ZiPhone 3.0. Click on “Do it ALL” as shown below.

You`ll see lot of white text scrolling by, once the procedure is finished, you will have a UNLOCKED, JAILBROKEN iPhone with firmware 1.1.4.

You will notice that, ZiPhone automatically installs Installer

You can use installer to install various applications.

In the next post, I`ll tell you how to access the iPhone via SSH and install applications via SSH.
Also I`ll give a list of most wanted applications on the iPhone. Till then Cya

Congratulations !