Ok so I have a new 3G its on a O2 sim. And working.
Before I try to hack it.

Is there anyway for me to take a system dump.
So that if things go south I can restore to my last virgin state.

Im not too smart when it comes not NOR, boot loaders etc. But I know the PC inside out. Im guesing the NOR is like your Bios. And your hack by writing stuff to this memory area. And things can go south sometimes.

Before you say no it cant be done.
Can you have a look at the way these guys are doing it

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Put your iPhone in Recovery Mode
2. sudo ./loadibec openiboot-2g.img3
- Or -3g, -ipod, depending on your platform.
3. sudo ./oibc
4. nor_read 0x09000000 0x0 1048576
5. ~norbackup.dump:1048576
- This will create a file called norbackup.dump in your
current directory. GUARD IT WITH YOUR LIFE.
6. install
7. After 'install' has finished, type in: reboot.
8. You ought to see the openiboot menu.
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Can we do something similar.
And say things stop working for any reason we use the same way to restore back our original image ?
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If you have any problems you can restore to the original firmware/system (for 2.2.1 using itunes or if you need 2.2 for unlock purposes, search for a download site and you will get the .ipsw files from somewhere and use 'shift key' restore) there is no need to dump anything from iPhone. Once you restore, none of the JB stuff is left on the iPhone and you are back to factory state :-)

scudder I dont think you get what I mean.

I have seen many instances where you have a working phone.
You hack it.
Next thing you know is your wifi is gone your blue tooth is gone.
You can DFU restore till the cows come home but you cant get the phone to get back the functionality it has lost be it Wi/Fi or blue tooth or the mic.

The only solution is custom s/w writen by the Dev Team that goes into the NOR or areas not even apple / itunes / dfu tocuhes and fix it.

Im talking about backing up this area of the phone.

Ah, ic. I have just been reading some of the WiFi/BT failures on here... hadn't heard of that until today.