Restore iPhone 4s to iOS 8.4.1 not working even in DFU Mode

Hello Panha iOne,

It sounds like your phone is jailbroken and you want to erase it and install a fresh official copy of iOS but keep getting error code -1. I would use the troubleshooting steps for that error number from the following article:

Get help with iOS update and restore errors

Check for hardware issues

Errors: 1, 3, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 53, 56, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.

Your device or computer might have a hardware issue that stops the update or restore from completing.

1. Check that your security software and settings aren't blocking your device from communicating with the Apple update server.
2. Then try to restore your iOS device two more times while connected with a cable, computer, and network you know are good.
3. Make sure that your security software and settings are allowing communication between your device and update servers.
4. If you still see the error message when you update or restore, contact Apple support.

If you still see the error message, check for outdated or modified software.

Thank you for using Apple Support Communities.

I appreciate the update Panha iOne. Next I would use this section of the same article since it mentions another one of the errors that you are getting, error 2009.

Check your USB connections

Errors: 13, 14, 1600, 1601, 1602, 1603, 1604, 1611, 1643-1650, 2000, 2001, 2002, 2005, 2006, 2009, 4005, 4013, 4014. You might also see a message that includes "invalid response."

If the USB connection between your device and computer is interrupted, you might not be able to update or restore.

To narrow down the issue, try different equipment:

• Use the USB cable that came with your device, or a different Apple USB cable.
• Plug your cable into a different USB port directly on your computer. Don't plug it into your keyboard.
• Try a different computer.
• Solve other issues with the USB connection, then with your security software.

Get help with iOS update and restore errors - Apple Support

Now, the last thing that I can think of to do would be to try restoring using Recovery Mode to see if that will 'force' the update through:

If you can't update or restore your iPhone, iPad, or iPod touch

If none of that works then your phone will need service:

iPhone Repair and Service - Apple Support

many people also have this error as I am,I went to many software specialist but in vain, I wish apple put solutions to this problem in the next IOS 9 as I believe it is intended.

Unfortunately, the big company who called Apple bricks his devices.

As I write in another post the problem begin from faulty firmware from Apple, (see update baseband chip), big number of IOS devices (especially the iPhone 4s) have problem with baseband chip.

Apple should take the responsibility and repair all this devices with this problem with own expense.

Regards