Apple unsigns iOS 18.3, ending firmware downgrades from newer iOS 18.3.1 release
Apple just last Monday released iOS & iPadOS 18.3.1 to the general public to address a security concern in which an attacker would disable USB Restricted Mode on affected devices, potentially opening users of these devices up to forms of malicious activity.
Unsurprisingly, Apple’s launch of a new software update also means that the Cupertino-based company has moved to prevent firmware downgrades to any older versions of iOS or iPadOS, which means that starting today, customers can no longer install any firmware besides iOS or iPadOS 18.3.1 on their iPhone or iPad unless said device doesn’t physically support it. This means that downgrades to iOS & iPadOS 18.3 and older is no longer possible.
iPhone and iPad owners have long used firmware downgrades as a means of installing jailbreakable firmware on their device so that they can install hacks and add-ons that unlock capabilities Apple hasn’t readily provided for end users in official software updates. On the other hand, Apple really hates when users do this, so they do everything they can to prevent firmware downgrades by using a server to deny firmware downgrade requests.
While there was once a workaround in which a user could save SHSH blobs for their device and then spoof an approval with those blobs, newer devices have updated Secure Enclave Processor (SEP) systems that complicate the process so much that this is no longer possible. Instead, the only way to install unsigned firmware these days is to upgrade to it within 90 days of unsigning using the DelayOTA method.
Blocking firmware downgrades also means that Apple can corral the masses into installing software updates more regularly, which makes the company look good to its shareholders when reporting software adoption numbers. Of course, those numbers may have looked a little different if Apple had given its users a choice, and this is something we wish they’d do, however unlikely such a thing seems.
Jailbreaking aside, firmware downgrades can be an essential troubleshooting tool when a newer firmware update breaks something important that a user relies on. While uncommon, there have been a lot of documented cases of this happening over the years, necessitating the end user to literally return to a previous firmware just to remedy the problem. Examples of those include:
- iPadOS 18.0 bricking M4 chip-equipped iPad Pros
- iOS 16.0 over-prompting users on clipboard access when pasting copied content into another app
- iOS 14.7 breaking the Apple Watch’s ability to be unlocked with the host iPhone’s Touch ID sensor
- iOS & iPadOS 13.2 imposing incredibly aggressive background management on backgrounded apps
We’re fortunate that Apple even provides a 1-2 week signing window following a firmware release, but since we think that we should be able to install any firmware version we want on the devices we pay for, it should be a given that gatekeeping firmware downgrades is fundamentally anti-user and only serves to furnish corporate interests. That’s why we think this needs to change.
Until that happens, however, you can visit the IPSW.me website to see what firmware is or isn’t being signed for your device, and you can also use our dedicated Downloads section to download any firmware that you might need for your project.
Source link: https://www.idownloadblog.com/2025/02/17/ios-18-3-unsigned/
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