iOS Installation Guide: Complete Walkthrough

A full restore with an IPSW file replaces your iPhone’s entire operating system. It’s the most reliable fix for software corruption nothing else can touch, and it wipes your data if you skip the backup. This guide covers the whole process: preparation, the restore itself, and post-restore setup. Restoring an iPad instead? The process is nearly identical; follow the iPadOS installation guide.

Before You Start

Back up first, because restoration erases everything.

• Computer backup (recommended): connect the iPhone, open Finder or iTunes, select the device, click Back Up Now. Enable Encrypt local backup so passwords and health data are included
• iCloud: Settings > [Your Name] > iCloud > iCloud Backup > Back Up Now, and confirm the timestamp after it finishes

Full details in our backup guide. If you’re downgrading rather than restoring, note that backups made on newer iOS versions may not restore onto older ones, so export irreplaceable photos and files manually too.

You’ll also need:

• Windows 10+ with current iTunes or the free Apple Devices app (Microsoft Store), or a Mac with Finder
• An original Apple USB cable, plugged directly into the computer
• ~10 GB free on the computer, iPhone charged above 50%
• The correct IPSW file for your exact model

Get the Right IPSW File

1. On the iPhone: Settings > General > About. Note the Model Name, then tap Model Number for the technical identifier
2. Download the matching file from dotIPSW’s iPhone firmware pages
3. Verify before installing: filename matches your model, extension is .ipsw (not .zip or .rar), and compare the SHA-256 checksum. Our integrity guide shows how, or use the browser-based verifier

If you’re installing an older version, confirm it’s still signed on the signing status page; unsigned versions refuse to install, no matter how perfect the file is.

Restoration Methods

All three use the same file-selection trick: hold Shift (Windows) or Option (Mac) while clicking, then choose your IPSW.

Method 1: Standard Restore (from a working iPhone)

1. Connect the iPhone, unlock it, tap Trust if prompted
2. Select the device in Finder or iTunes
3. Click Restore iPhone while holding Shift/Option
4. Select the IPSW file, confirm, and let it run

Method 2: Recovery Mode (iPhone won’t start normally)

1. Connect the iPhone to the computer
2. Enter Recovery Mode (combos below)
3. When the computer detects the device, hold Shift/Option, click Restore (not Update), select the IPSW

Method 3: DFU Mode (corruption that survives Recovery)

Same restore flow, but from DFU mode; the screen stays black while the device waits. Enter DFU with the combos below, then hold Shift/Option, click Restore, and select the file. A mistimed DFU attempt is harmless; the phone just boots and you retry.

Button Combinations

iPhone 8 and newer (all Face ID models, iPhone SE 2nd/3rd gen):

Recovery:

1. Press and quickly release Volume Up
2. Press and quickly release Volume Down
3. Press and hold the Side button until the recovery screen appears

DFU:

1. Press and quickly release Volume Up
2. Press and quickly release Volume Down
3. Press and hold the Side button for 10 seconds
4. While still holding Side, press and hold Volume Down for 5 seconds
5. Release Side, but keep holding Volume Down for 10 more seconds

iPhone 7 / 7 Plus:

Recovery:

1. Press and hold the Side button and Volume Down together
2. Keep holding until the recovery screen appears

DFU:

1. Press and hold the Side button and Volume Down together for 8 seconds
2. Release the Side button, but keep holding Volume Down for 10 more seconds

iPhone 6s and earlier (incl. SE 1st gen):

Recovery:

1. Press and hold the Home button and Sleep/Wake button together
2. Keep holding until the recovery screen appears

DFU:

1. Press and hold the Home button and Sleep/Wake button together for 8 seconds
2. Release the Sleep/Wake button, but keep holding Home for 10 more seconds

(Official Apple reference: Apple Support.)

What the Restore Looks Like

Total: roughly 45–60 minutes, with several restarts. Do not disconnect at any point. Keep the computer awake and plugged in.

If an error appears, note the code and look it up in our installation error guide rather than guessing; most codes map to a cable, software, or signing issue with a specific fix.

After the Restore

1. Walk through setup: language, Wi-Fi, Face ID/Touch ID, passcode, Apple ID
2. At Apps & Data, choose Restore from iCloud Backup, restore from the computer backup, or choose Set Up as New iPhone if you want a clean slate
3. Update iOS and all apps, then test the essentials: calls, Wi-Fi, camera, Apple Pay
4. Check battery health (Settings > Battery) and free storage
5. Make a fresh backup once everything works; that’s your new safety net

If the iPhone runs slowly right after setup, give it a few hours; background indexing looks exactly like a performance problem and resolves itself.

When to Get Help

Stop troubleshooting and contact Apple Support or an authorized service provider when: restores fail repeatedly with the same error, the device reports hardware errors, Activation Lock appears on a device you don’t have credentials for, or the phone has been dropped or wet. Software procedures can’t fix hardware.

Handled calmly (verified file, solid backup, no interruptions mid-flash), an IPSW restore is one of the most reliable fixes in the iOS toolbox.