Have similar problem with the asker in Apple support community while you want to reatore Firmware?
I have a 32GB Wi-Fi iPad, and I tried to install the iOS 4.2.1 directly from iTunes (latest version), and does not work, it shows me an error "unknown error (40)".
I've tried switching USB ports and Mac computer.
Can anyone help me?
This article here would help you to restore iPad firmware step by step, no matter the reason why you wanna restore firmware is:
- Open iTunes;
- Plug your new iPad to Mac;
- Hold the Home button down the bottom of the iPad screen and the sleep/wake button on the top side of iPad until the iPad screen turns black, keep holding;
- When you see the Apple logo appears again, you can release the sleep/wake button but keep holding the Home button until the iTunes on your Mac recognize the device, at that time, your iTunes will pop up a window showing you your new iPad needs to be restored;
- Follow the instruction which your iTunes tells, download the latest firmware;
- Restore firmware on your iPad then.