Apple stops signing iOS 16.5.1 in bid to end downgrades from iOS 16.6

Just last week, Apple released iOS & iPadOS 16.6 to the general public with a bevy of security patches to make the company’s mobile devices more secure.

iOS 16 firmware downgrade

But just as you might come to expect from the Cupertino-based company, Apple has stopped signing the predecessor firmware iOS & iPadOS 16.5.1 in a move that prevents iPhone and iPad owners from downgrading their firmware.

Starting today, should someone try to downgrade their iPhone or iPad from iOS or iPadOS 16.6 to iOS or iPadOS 16.5.1 in Finder on macOS or iTunes on Windows, they’ll be greeted instead by a message that urges them to download and install the latest update.

We should note that unofficial ways of installing unsigned firmware do exist, such as utilizing futurerestore on older devices to perform a firmware downgrade or using DelayOTA on any device to perform a firmware upgrade, however newer non-checkm8 devices don’t currently have a downgrade option because of additional security layers implemented by Apple.

In general, Apple blocks firmware downgrades with the firmware unsigning method because they don’t want iPhone and iPad users installing older firmware that can be jailbroken. It’s a somewhat strange stance given not only that Mac users can freely downgrade their operating system version, but also because users individually own their device and should be able to install whatever version of iOS or iPadOS they want on it.

Jailbreaking aside, legitimate purposes do exist for downgrading one’s firmware, such as regaining lost functionality after a buggy software update. Many examples where firmware downgrades would have remedied these situations include:

  • 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

Unfortunately, as Apple continues to obfuscate the downgrade process with complex firmware signing schemes and additional on-device hardware that needs exploiting, doing this becomes a lot more difficult.

At iDB, we have long held the stance that users should be able to install whatever version of iOS or iPadOS that they want on their device, but as long as Apple isn’t bound by government action in the United States, it seems unlikely that they will allow users to install their preferred firmware version on their own device.

As always, you can check to see which version(s) of iOS or iPadOS are being signed for your device via the IPSW.mewebsite. You can also download any version of iOS or iPadOS that you if it be looking for on our Downloads page.

Are you upset by Apple’s decision to stop signing iOS & iPadOS 16.5.1? Let us know why or why not in the comments section down below.