iPhone XS Max IPSW Files Signed by Apple

[KellMOO]

Are IPSW files that are signed by Apple, once downloaded to your personal computer...do they remain signed forever?

I was under the impression that a signed IPSW file, means the digital signature is attached to each IPSW file and not somehow associated to what the Apple Server says at that moment in time.

Meaning once Apple stops signing the file officially from their website, will my previously downloaded IPSW signed file remain signed for me and still be usable for me using Recovery Mode down the road if needed.

I'm new to the Apple Community having bought my first iPhone and was looking for clarification on this question. Should I bother downloading signed IPSW files when they are posted and archive them or is it a waste of time because the signing is all controlled by Apple Servers?

I'd appreciate some insight on this topic.

Thank you!

 

[Fat_Guy]

I assume you want to roll back to a previous version of iOS.


If Blackberry is anything to go by many have tried and none succeeded in messing around a signed OS. Would be nice if they could.



I believe these signed files serve a security purpose so only unsigned files could be used to roll back for instance.


BTW, you are in the wrong place for this question. Apple is as proprietary as Blackberry and don’t take kindly to folk messing around with iOS….

 

[Fat_Guy]

I reread your question. I suppose a signed IPSW should work as long as no changes were made to the phone. Mess with the man and all bets are off….


Also - I’m not a tech expert. 🤣

 

[Nermal]

The phone-specific signature required to install the OS is not actually part of the IPSW but is rather downloaded "on demand". Your IPSW doesn't remain signed, because it was never fully signed in the first place.

 

[KellMOO]

Let me try to explain a little better. But yes I would like to downgrade from 16 to 15 iOS as the touch sensor feels delayed / lagging after upgrading to 16.5.1(c).

The IPSW files are still being provided directly from Apples Servers here, as an example:

https://updates.cdn-apple.com/2023SummerFCS/fullrestores/042-16992/32DCAE29-DDC4-4E95-99F6-93B20EC94E90/iPhone11,2,iPhone11,4,iPhone11,6_16.6_20G75_Restore.ipsw

The website I'm visiting is IPSW.me and they have a nice user interface that simply links your device to whatever version of iOS you want to download direct from Apple (See Example attached).

 

[eyoungren]

Are IPSW files that are signed by Apple, once downloaded to your personal computer...do they remain signed forever?

I was under the impression that a signed IPSW file, means the digital signature is attached to each IPSW file and not somehow associated to what the Apple Server says at that moment in time.

Meaning once Apple stops signing the file officially from their website, will my previously downloaded IPSW signed file remain signed for me and still be usable for me using Recovery Mode down the road if needed.

I'm new to the Apple Community having bought my first iPhone and was looking for clarification on this question. Should I bother downloading signed IPSW files when they are posted and archive them or is it a waste of time because the signing is all controlled by Apple Servers?

I'd appreciate some insight on this topic.

Thank you!

No, they do not remain signed. That isn't how it works.

Any time you try to install from an IPSW there's a check to Apple's servers. If it's still signed on Apple's servers then you can proceed. If not, there is a halt. If there is no internet connection, there is no check and you won't be allowed to proceed.

From early days, there were ways around this - specifically keeping blobs. These are little bits of code that reference your device and the version of iOS when they were saved. It's designed to trick things into allowing a reinstall. Don't have them, no reinstall of unsigned IPSWs. And if Apple isn't signing it, it doesn't matter if it was signed when you put it on your computer.

But…it no longer really matters with iPhones from the iPhone 6 series on. EVERYTHING changes with APT Ticket and that happened with iOS 7. If you have an older device and you have blobs or some other method than this might still be possible.

Newer iPhones - no.

Here's where it all started…it's old, but it shows where Apple got aggressive about shutting all this down.

Where did my iOS 6 TSS data go?

www.saurik.com

PS. Apple's moved on from APT Ticket. It's a primary reason there are no fully untethered jailbreaks anymore from iOS 9.0.2 to now.

 

[KellMOO]

No, they do not remain signed. That isn't how it works.

Any time you try to install from an IPSW there's a check to Apple's servers. If it's still signed on Apple's servers then you can proceed. If not, there is a halt. If there is no internet connection, there is no check and you won't be allowed to proceed.

From early days, there were ways around this - specifically keeping blobs. These are little bits of code that reference your device and the version of iOS when they were saved. It's designed to trick things into allowing a reinstall. Don't have them, no reinstall of unsigned IPSWs. And if Apple isn't signing it, it doesn't matter if it was signed when you put it on your computer.

But…it no longer really matters with iPhones from the iPhone 6 series on. EVERYTHING changes with APT Ticket and that happened with iOS 7. If you have an older device and you have blobs or some other method than this might still be possible.

Newer iPhones - no.

Here's where it all started…it's old, but it shows where Apple got aggressive about shutting all this down.

Where did my iOS 6 TSS data go?

www.saurik.com

PS. Apple's moved on from APT Ticket. It's a primary reason there are no fully untethered jailbreaks anymore from iOS 9.0.2 to now.

Thank you for you’re amazing explanation. I’ve been losing sleep trying to figure this out reading lots of articles.

Also as a previous Android user, switching to Apple iPhone has been a learning experience.

I switched to Apple iPhone from Android with the intent of learning something new.

I can’t say that I’m disappointed.

Many thanks to you and all the great people that contribute.

Kelly

 

[FeliApple]

This is Apple’s most pathetic, harmful, and malware-like policy, sadly this hasn’t been possible for years, like @eyoungren said.

Imagine how cool it would be if you could download signed IPSWs and install them whenever you like, even after they’re unsigned!

 

[eyoungren]

This is Apple’s most pathetic, harmful, and malware-like policy, sadly this hasn’t been possible for years, like @eyoungren said.

Imagine how cool it would be if you could download signed IPSWs and install them whenever you like, even after they’re unsigned!

It reduces the workload of tech support to have as many customers as possible on the same (or close to) version of iOS. Apple also states that when we buy an iPhone all we are buying OS-wise if a license to use iOS.

But yeah, it'd be nice to have whatever version on your device you'd like to run.

 

[Fat_Guy]

It reduces the workload of tech support to have as many customers as possible on the same (or close to) version of iOS. Apple also states that when we buy an iPhone all we are buying OS-wise if a license to use iOS.

But yeah, it'd be nice to have whatever version on your device you'd like to run.

Some websites say they can… 😳



Anyway, you are asking for trouble when you mess with proprietary operating systems. Here is one example from Blackberry:



So Blackberry gets out of the cellphone market but still exists as cyber security. We could never crack OS 10 probably because of a QNX proprietary issue, but this was a few years ago.


Anyway, it turns out Android was installed on a bunch of Passports with the square screen. Technically this would invalidate the device as Android needs a rectangle, but probably out of curiosity they let Blackberry install it and make it work.


So guess what, Blackberry gets out of handsets and those Android Passports start to go missing with some ending up on eBay. So they get new owners who just couldn’t keep it a secret they had a Passort running Android!


What does Blackberry do? They hunted them all down and confiscated the devices!


I have no question that Apple is the same way. Also, I suppose it’s some kind of crime to repurpose iOS for some use Apple never intended. So I would stay away from this kind of stuff.


Supposedly some guy has installed Android on a Passport now - he better be living in Russia! 🤣 Better yet, he should take his talents and work on Pinephone’s Linux kernel as that is where talent is needed. The bad boy image in programming don’t get you no woman!

 

[eyoungren]

Also, I suppose it’s some kind of crime to repurpose iOS for some use Apple never intended. So I would stay away from this kind of stuff.

The Librarian of Congress has ruled that jailbreaking is a legitimate and legal exception to the Digital Copyright Millennium Act (DCMA). This exception has been renewed several times and is current. Therefore jailbreaking an iOS device, whether Apple likes it or others disprove of it is legal in America. Other countries, IDK.

And to downgrade to an unsigned IPSW (if you can) requires jailbreaking.

Several years back Apple also changed it's policy regarding service of jailbroken devices. They will fix a jailbroken device and it does not invalidate your warranty. The only exception is if a jailbreak caused your problem. And the most they will ask you for is to restore your device before starting work on it.

So, you crack a screen on your jailbroken device, Apple will fix it. I tested this in 2015. I got a brand new phone out of the deal.

Considering that the tide has turned and a lot of former jailbreakers (myself included) are not jailbreaking their devices anymore, Apple has pretty much won the 'war' on this.

It's always at your own risk of course, and if you jailbreak you take security and support into our own hands. But Apple isn't standing over you waiting to hammer you down if you mess with an IPSW!

 

[KellMOO]

This is great information.
Thank you for sharing your thoughts.

 

[winxmac]

A downloaded IPSW is only good while Apple is signing the version... Downgrade through iTunes/Finder will only work/proceed so long as Apple has signed the version... Once it is no longer signed by Apple, it will just be a space waster of your storage device... Unless Apple re-signs the version by mistake, which happened a few years ago...

Android, particularly Samsung, has no signing window however, once you are past a certain security level, you can only downgrade within the same security level... If you are on security level F, you can downgrade to any version of security level F... Once you upgraded and are now on security level G, you cannot downgrade to go back to security level F...

Between Apple and Samsung, downgrading is easier with Apple provided that Apple is still signing the version you want to downgrade to...