How to reinstall iOS on iPhone

Максим Исаев
Reading time: 4 min

General recommendations for reinstalling the operating system on iPhone

Educational material of the Bgacenter iPhone Repairing School.

Many problems that happen with smartphones are of a software nature. And repair does not require physical intervention in the device. In this case, you can restore the phone by updating its operating system.

When to reinstall the operating system

Firmware or software repair is often used during phone repair. When answering the question of how to reinstall the iOS, it is first of all important to understand in which cases reinstallation is required, and when it is better not to do this.

Typically, the operating system is reinstalled in the following cases:

  • during a system failure to restore to working condition,
  • to restore the iOS, after a failed recovery “on the air”,
  • to update iOS to the latest version,
  • in case the password code for iPhone is entered incorrectly several times,
  • to get an error code, and troubleshoot an iPhone.


Teachers of bgacenter recommend to reinstall iOS on client phones or tablets exclusively during repair.

IOS reinstallation on the serviceable client device is carried out only with coordination of all risks with the client!

If you have previously replaced the NAND Flash chip on this phone to repair or increase memory, it is likely that the Wi-Fi and Bluetooth MAC addresses are incorrect. During the iOS reinstallation process the phone may not be able to go through activation and will die.

If the phone is disassembled, it makes sense to examine the board under a microscope. It is important for us to see the presence or absence of compounds around the chips: NAND Flash and MODEM. Perform the iOS reinstallation exclusively through the cable. From experience, when reinstalling the iOS “over the air ” via Wi-Fi, various bugs may occur.

Programs for iOS reinstalling

For the firmware reinstallation of devices based on iOS, two programs can be recommended: this is the official iTunes and the Chinese analogue of iTunes, free software 3uTools.

iTunes can be downloaded from the official Apple website at this link

In our opinion, 3uTools is the most optimal program. This software can be downloaded on the developer’s website at this link.

This program has a wide range of features. We will describe how to use 3uTools in more detail in the following articles.


iOS reinstallation sequence

What needs to be done before the reinstalling iOS:

  • Get an Apple ID for iCloud (account name and password) or ask a customer to sign out of iCloud. To do this, go to Settings → Apple ID → Sign out.
  • Back up iCloud before exiting.
  • Conduct express diagnostics of the phone (more detailed in this article).
  • Charge the battery by at least 50%. If it is possible to measure the voltage of the battery, it should be at least 3.8 Volts (or better 4.0 Volts).
  • Use the original wire for reinstallment iOS.
  • Update iTunes or 3uTools to the latest current version.

The reinstalling process:

  • Turn off the phone.
  • Enter the phone into Recovery Mode. To do this, on the off phone, hold down the Home button, hold it and then connect the cable to the laptop, with the pre-connected wire in the lightning connector (8-pin connector).
  • The computer must independently determine the connected device and that the phone is in Recovery Mod. This will bring up the cable image and iTunes icon on your phone screen.
    Perform further activation after Apple logo appears.

Files of downloaded firmware via iTunes are stored in the following folders:

  • mac os x: user>lybrary>itunes>iphone sofware update
  • Windows 7: c:\users\Name of user\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates
Recovery Mode

Recovery mode is designed to restore the working state of the iOS device in the case of software failures. This mode is used when the iPhone or iPad does not boot in normal mode (the display and pressing the buttons do not respond).


In order to learn how to flash the iPhone, it is enough to read this article and answer the control questions (for students of the program: Modular and software repair).

When performing software repair of the device with the iOS operating system, you should follow the checklist above.

Correctly reinstall the operating system on phones and tablets, so that they do not die, and what to do if this happens, we study in detail during the training on diagnosis and BGA soldering.

Rate the material
0 votes, average: 0.00 out of 50 votes, average: 0.00 out of 50 votes, average: 0.00 out of 50 votes, average: 0.00 out of 50 votes, average: 0.00 out of 5


0 Комментарий
Inline Feedbacks
View all comments