What is iTunes backed up? Firmware?

Firmware is not backed up. The backup is your library's indexes, memos, and so on. If it's an iPhone, there's also Contacts and more.

iTunes Backup: Used to back up system settings and some application data in your iOS device.

Firmware refers to the installation package of the iOS system, which can only be installed on the iOS device through iTunes.

iOS is a mobile operating system developed by Apple Inc. Apple first announced the system at MacWorld on January 9, 2007, and was originally designed for the iPhone, and later applied to the iPod touch, iPad, and Apple TV.

iOS, like Apple's Mac OS X operating system, is a UNIX-like commercial operating system. Originally, this system was called iPhone OS, because iPad, iPhone, iPod touch all use iPhone OS, so the 2010WWDC conference announced that it was renamed iOS (iOS is a registered trademark of the network equipment operating system of Cisco in the United States, and Apple has been authorized by Cisco).

1. First of all, we connect the iPhone or iPad we want to backup to the computer.

2. Install and open the iTunes software on your computer, then click the small phone icon at the bottom of the title bar, then select "This Computer", and click the "Back Up Now" button.

3. The backup needs to delay us for some waiting time, please be patient.

4. Then open "This Computer" on the computer desktop (if my computer system is win10, if the XP system is the system, it is to open the "My Computer" on the desktop, and the win7 system is to open the "computer" on the desktop), and the computer is set to show the hidden items. The following figure shows how to set up Win10, if you have an XP system, please click "Tools", "Folder Options" menu, and then set to show all hidden files or folders under the "View" tab.

7. Then we can export any file or folder in the iTunes backup data to the computer through the export function of the software.

For the following steps, please refer to:

Double-click the iTunes icon to enter iTunes. Connect the phone to the U port of the computer with a data cable. The phone screen pops up "Do you want to trust this computer?" Click "Trust".

In the upper left corner of the iTunes interface, a phone icon is displayed, tap to enter.

The first interface that iTunes displays is a summary under the settings, and the right side will show the basic information of the phone, such as capacity, ** number, serial number, etc. The following is the backup column, and you can choose "iCloud" backup and "This computer" backup in the automatic backup.

Select "This Computer", that is, the complete backup of your iPhone will be stored on this computer, you can encrypt the iPhone backup, or you can change the password. Then select Back Up Now.

In the pop-up page, select "Do not back up the app".

The progress of the backup is displayed in the blue progress bar above iTunes, and there is a text prompt above it that says "Backing up my iPhone". This process takes a little longer, so be patient for a while.

When the backup is complete, the latest backup of your iPhone is displayed below.

Right-click on the iPhone in the left column and click Backup.