i get error 20... what do i do?

You need to downgrade iTunes.

We made a tutorial over at iclarified if you wish to look at it. I would recommend following it because of the iTunes Library that needs to be saved.

N41

I can confirm what geircito said...with one addition: you need an UPDATED version of the patched zIphone! The one in the wild is for the BETA 2.0 versions.
I made a tutorial here, feel free to post comments on this thread. I will try to help anyone to avoid losing 2 days like me.

Does this work on the Ipod Touch?

I heard that iPod Touch users are stuck until pwnage 2.0 comes out

There are 3 guides like this! Either they need to be merged or some need to be closed. This is a good guide but please dont post when there are alrady some in existence...

I am trying with the tutorial.
When you say:
"4. Kick your phone out of DFU mode using the NON patche zIphone (or any other unlocking tool that does this)."
It means that when I have the error 1015 I have to use zyphone, not patched? At the end of this I have the iPhone with all its function except the telephone. When I try to use then the patched one I cannot complete the sequence. I am stuck: Someone help me?

Originally Posted by Niraj1117

i get error 20... what do i do?

I get the same thing, but I have done all that I was supposed to do: downgrade, restart computer, etc... but i still keep on getting this error 20 message... ay help?

Please help! I've been without my iPhone now for two days, and I'm really missing it! I'm an active member of the community, and I do searches. I even wrote a guide that it in the 'Genius Bar - HowTos, Guides and Tutorials' section on this board, a while back. This one has got me beat, though.

I bought an 8GB iPhone back in the 1.0.1 days from the States to use in the UK. A few days ago, I was on 1.1.4. ZiPhone act/jail/unlocked. After reading numerous posts about any O2 SIMs being able to be activated in 2.0, I did my reading and took the plunge. The upgrade went fine, but I was unable to activate. iTunes tells me I have an unsupported SIM. I have been to the O2 shop in the interim, and collected a different SIM to try that. Same message in iTunes.

I have no idea what is going wrong here. I seem to get conflicting information from each person I speak to, and none of the guides on this board seem to work for me.

I'm now in a position where I'm trying to restore to 1.1.4, and I'm following the instructions in various guides. Downgrade to iTunes 7.5 > DFU mode > Restore 1.1.4, but I just keep getting error 1600. I have tried different USB ports, back to DFU mode each time...

I did the original hacking of 1.1.4 with ZiPhone. Are we coming to the conclusion that ZiPhone-hacked 1.1.4 iPhones are having problems? Once 2.0 has been put on them?

Has anyone who used ZiPhone on 1.1.4 successfully been able to regress from 2.0?

Please please help! I'm lost without my phone!

Originally Posted by killingspyder

I get the same thing, but I have done all that I was supposed to do: downgrade, restart computer, etc... but i still keep on getting this error 20 message... ay help?

I get error 20 when either a) I hadn't put the phone into DFU mode properly (i.e. black screen) and, b) when I hadn't downgraded iTunes to 7.5 and was using 7.7.