How to Extract Data from an IPSW Firmware File

July 3, 20266 min read

As we detailed in our guide What is an IPSW file, Apple's firmware packages are essentially just renamed ZIP archives. If you are an app developer looking for native Apple UI assets, or a security researcher looking to analyze the iOS filesystem, you can extract the contents of an IPSW file directly on your computer.

What you will find inside

After extraction, you'll see several DMG (Disk Image) files. The largest DMG is the Root Filesystem, which contains the entire iOS or macOS structure. Historically, Apple encrypted this root filesystem, requiring decryption keys to mount it. However, since iOS 10, Apple leaves the root filesystem DMG unencrypted, making it trivial to explore.

Step-by-Step Instructions

1. Download the IPSW

Download the desired firmware from our directory to your Mac or PC.

2. Rename the Extension

Locate the file, right-click it, and rename the extension from .ipsw to .zip. If your OS warns you about changing extensions, confirm the change.

3. Extract the Archive

Double-click the .zip file to extract it using the built-in Archive Utility (Mac) or File Explorer (Windows).

4. Locate the Root DMG

Open the extracted folder. You will see 2 or 3 .dmg files. Look for the file with the largest size (usually 3GB to 7GB). This is the root filesystem.

5. Mount the DMG

On a Mac, simply double click the largest DMG to mount it. It will appear as a new drive on your desktop, and you can browse the entire iOS file structure (e.g., /Applications, /System, /Library).

Frequently Asked Questions

Can I extract IPSW files on Windows?

Yes, you can rename and unzip the file on Windows. However, Windows cannot natively read Apple's DMG disk images. You will need third-party software like 7-Zip or TransMac to open the internal DMG files.

Can I modify the extracted files and repackage the IPSW?

You can repackage it, but you cannot install it. Altering the IPSW breaks the cryptographic hash. When iTunes checks the signature with Apple, it will be rejected, and the installation will fail.

Why are some DMG files inside the IPSW unreadable?

Prior to iOS 10, Apple encrypted the root filesystem DMG. To read these older firmwares, you need the specific decryption keys for that iOS version and device, which are usually crowdsourced by the jailbreak community.

Can I extract Apple default wallpapers from an IPSW?

Yes! Once you mount the root filesystem DMG on a Mac, you can navigate to /Library/Wallpaper to extract the uncompressed, original resolution wallpapers.

How do I extract the baseband firmware?

The baseband firmware is usually located in the 'Firmware' folder inside the unzipped IPSW. It typically ends in .bbfw and contains the modem software for cellular connectivity.

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