Thanks for checking out the post.

I have an iPhone 2G with firmware 04.05.04_G using baseband 2.2.1.

I downloaded iTunes 7.5 and ZiPhone to try and downgrade the baseband to 1.1.4 but I keep receiving error messages on iTunes when performing an option-restore.

This is really complicated and I've tried playing around when its plugged in and in DFU mode, using different USB ports as some forums suggested. Still no luck.

This is what I've been doing (please tell me what I'm doing wrong):

1. Hold power + home keys for 10 seconds. Let go of power key. Hold home key for 10 seconds.

2. Run ZiPhone (program entitled: ZiPhoneOSX patched by kIREmK 04.05.04_G [En].app). Check box next to "baseband downgrading". Hit start. Message comes up:
Loading zibri.dat.
i386
Searching for iPhone...
USBMuxListenerCreate: Permission denied
Working...
Please wait 2'30"."

3. iTunes message pop-up: '...in recovery mode...need to restore'. I hit option-restore, and select the iPhone1,1_1.1.4_4A102_Restore.ipsw file.

4. After I perform this function I always get some error message. Either 5, 20, 1015, 1600, 1603, 2005, etc.

I've tried so many times and always fail. Can someone please tell me how to do this? Or provide a link with step-by-step instructions? THANK YOU SO MUCH.

Update:

Now I am using the latest PwnageTool for Mac and iTunes 8.1 to unlock my iPhone 2G using 04.05.04_G (apparently you can do this, instead of having to manually use an older version of iTunes and ZiPhone to change the baseband). BTW, I managed to change the firmware to 2.2 instead of 2.2.1 (but not to the custom PwnageTool version).

So, I run PwnageTool, basically do everything that is stated on iClarified (iClarified - iPhone - How to Unlock/Jailbreak Your 2.x.x 2G iPhone (Mac) [Updated 2.2.1]), but towards the last step, I constantly received error messsages when doing an option-restore to the custom 2.2 ipsw file. PLEASE, what am I doing wrong?

Thanks again.