iTunes Error Code 21

[SK4DJ]

Im trying to restore my iPhone 4 back to the iOS 5.0.1 downloaded iPSW from here at modmyi.com however im getting the Error code 21. THe iOS its running right now is jailbroken. I tried DFU but it gave me error code 1600 any ideas on how to resolve the error code?

[iYeow]

Describe the process of your update to 5.0.1. You should be restoring from Homescreen or recovery mode.

[SK4DJ]

Connected iPhone while its on to Macbook
Downloaded the IPSW from Modmyi.com (iPhone 5.0.1 9A405)
Clicked Option + Restore and selected the IPSW
iTunes extracts the IPSW Software
Itunes Verifies the IPSW with Apple
ITunes prepares iPhone for restore (Recovery Mode)
iTunes reports unknown Error code 21

[iYeow]

Have you checked your hosts file is not pointed towards cydia ?

[SK4DJ]

How can I check

[iYeow]

Do you have tiny umbrella installed ?

[SK4DJ]

Yes I do

[iYeow]

Go to advance tab in TU and uncheck : set hosts file to cydia and close TU. This is to make sure you are letting apple verify your restore.

[SK4DJ]

Ok so I went to TU and unchecked the box. Closed TU connected the iPhone again to iTunes and did the whole process but I still got error code 21. I went back to TU and the box was still unchecked

[iYeow]

Did you close itunes and reopen it or do a reboot to see if it works.

[SK4DJ]

Ok so I closed down iTunes and reopened it as well as rebooted the iPhone and tried to restore it and still got the error code 21.
\

[iYeow]

Try it on a pc if you have one.

[SK4DJ]

Should I also just try using the stock restore IPSW iTunes offers or should I just keep choosing the IPSW I downloaded from Modmyi?

[iYeow]

Redownload your stock ipsw from any source like apple or iclarified firmware. Do you have the latest 10.5 itunes installed ?

[SK4DJ]

Lol ok, so here's what just happened. I tried it once again and it gave me Error Code 21. However, I always noticed how iTunes left my iPhone on Recovery mode and every time iTune would leave it like that I would use TU to kick it out of Recovery Mode. So after another attempt that iTunes left me with error code 21 and the iPhone in Recovery Mode I decided not to use TU to kick it out of Recovery Mode and just disconnected and reconnected the iPhone back in. iTunes identified the iPhone in recovery mode and I did the restore again, this time it worked (and I had also left "SHSH Cydia" option unchecked, even though at first it still gave me the 21 error code before I tried it agan and it worked with iPhone in Recovery Mode). I could have sworn that I had already tried restoring the iPhone while it was in recovery mode by doing the same process and still giving me the error code 21, but then again I am really tired and tried so many times that everything is a blur right now lol but I guess thats the way to by pass error code 21? lol

Thanks a lot for staying along and helping me brainstorm a bit iYeow

I guess the question now is should I jailbreak now and then Restore to the old backup?

[iYeow]

Setting as a new iphone is recommended although backup restore will work too. Glad you are got it working.