how to fix 29 error?

Hello, reddevi.

Thank you for visiting Apple Support Communities.

The usual cause for error 29 on a restore of an iOS device is a security software conflict or host file modifications. Below, I have included a couple articles that will walk you through some troubleshooting steps.

Resolve issues between iTunes and security software

http://support.apple.com/kb/TS3125

Check your hosts file

After you update iTunes to the latest version, check the hosts file to make sure your computer can contact the update server.

If you’re using a Windows computer, follow the steps in this Microsoft support article (note that resetting thehosts file will affect software services that rely on hosts file redirects). If you're using Windows on a business computer, consult your IT department to be sure applications will work correctly after you reset the hosts file.

If you're using a Mac, follow these steps:

1. In the Finder, choose Applications > Utilities.
2. Open Terminal.
3. Enter this command and press Return:
   sudo nano /private/etc/hosts
4. Enter the password you use to sign in to your computer and press Return. You won't see text appear in the Terminal window when you enter the password. Make sure you use a nonblank administrator password.
5. Terminal will display the hosts file.
6. Navigate using the arrow keys and look for an entry containing “gs.apple.com”.
7. Add the # symbol and a space ("# ") to the beginning of the gs.apple.com entry.
8. Press Control-O to save the file.
9. Press Enter when asked for the filename and Control-X to exit the editor.
10. Restart your computer.
11. Try to update or restore your iOS device again.

Error 3194, Error 17, or "This device isn't eligible for the requested build"

http://support.apple.com/kb/ts4451

If none of the steps resolved your issue please contact us here.

Cheers,

Jason H.