FutureRestore SEP and Baseband Compatibility List for downgrade

When considering downgrading iOS using FutureRestore, relying solely on SHSH2 blobs for your iPhone is insufficient. Equally crucial is the SEP and Baseband Compatibility, as it determines the success of the iOS downgrade process. It's essential to note that not all iOS releases align with the currently running firmware. Consulting the SEP and Baseband Compatibility List for FutureRestore downgrades can significantly enhance your chances of success. Please beware that downgrades from iOS 17 are not possible.

FutureRestore is a hacked version of idevicerestore, offering the capability to manually designate SEP and Baseband for the restoration process. This functionality enables the restoration of unsigned firmware onto devices, contingent upon the availability of a backup of the APTicket (SHSH Blobs). Additionally, it can replicate all the unique conditions of the APTicket, such as ECID, APNonce, and Board ID.

Let's illustrate this with an example. If you're currently running the latest iOS 16.7.5 on your iPhone 8, you have the option to utilize FutureRestore to downgrade to an unsigned iOS 16 version, ranging between 16.6.1 and 16.7.4. However, attempting to downgrade to versions below iOS 16.6.1, including iOS 16.5.1 and earlier, will be unsuccessful due to SEP and Baseband Compatibility issues. Downgrading to iOS 15 and iOS 14 is also not viable even with saved blobs.

In this scenario, upgrading from iOS 14.2.1 to unsigned versions like 14.3 through 15.7.2, or iOS 16 on an iPhone 8, is likewise not feasible due to SEP and Baseband Compatibility constraints. SEP and Baseband compatibility is essential, ensuring they are compatible not only with the latest or signed iOS version but also with the version you aim to downgrade to.

SEP and Baseband Compatibility Chart

iOS Signing Status is a tool that enables you to easily check the current signing status of IPSW firmware for a wide range of iOS devices, such as iPhones and iPads. Moreover, it offers the added advantage of allowing you to effortlessly download IPSW images (signed and not) for your iDevices. Experience the dynamic efficiency of iOS Signing Status, which automatically updates in real-time.

Legacy iDevices (up to iOS 12)

SEP and Baseband components exhibit compatibility spanning from iOS 11.3 to iOS 12.5.7, facilitating successful downgrades from the latest iOS 12 version to as far back as iOS 11.3. This capability extends to devices including the iPhone 5s, iPhone 6, and some iPads. However, it's important to note that iOS versions 11.0 to 11.2.6 are not supported and are consequently incompatible with FutureRestore resulting in a downgrade fail, forcing you to upgrade.

Moreover, the iPhone 5s, iPad Mini 2, and iPad Air 1 equipped with the A7 Chip can also install the signed (OTA) version of iOS 10.3. This iteration of SEP and Baseband exhibits FutureRestore downgrade compatibility with iOS 10.1 through iOS 10.3.2 on those iDevices.

Legacy iDevices (up to iOS 15)

Legacy iPhones and iPads operating on iOS 15 are susceptible to the checkm8 exploit. By utilizing saved blobs, you can employ FutureRestore Dev to downgrade from iOS 15.8.1 to versions spanning from iOS 14 to iOS 15.7. Notably, the iPhone 6s and iPhone SE with A9 Chip have the capacity to go even further down the version ladder, courtesy of the Limefix utility.

Legacy iDevices (up to iOS 16)

The cryptex for iOS 16.7.5 remains compatible with iOS 16.6.1, enabling the downgrade of iPhone 8, iPhone X, and certain mentioned iPads to versions ranging from iOS 16.6.1 to iOS 16.7.4 through futurerestore dev branch, provided that you have saved blobs. It's worth noting that iOS 16.6.1 is compatible with the most recent release of Dopamine 2 Jailbreak.

Note: After performing this action, the "About" section will display version 16.7.5. However, upon tapping the iOS version, it should indicate that the device is running on 16.6.1, accompanied by a note mentioning the presence of the 16.7.5 Rapid Security Response.

Warning: You can't use the nightly branch of futurerestore to downgrade iOS 16.7.5 to iOS 16.6.1, you have to compile the dev branch of futurerestore.

For iPhone X running iOS 16.7.5, you can use FutureRestore to restore to iOS 16.6.1 – iOS 16.7.4 versions and then signed ones. All SHSH blobs 16.5.x and lower are useless.

Current iDevices (up to iOS 17)

All iPhones and iPads equipped with SoC A12 through A17 and operating on iOS 17 or later versions are incompatible with iOS 16 and iOS 15. FutureRestore iOS 17 downgrade to iOS 16 or lower is not possible. On A12 and later, restoring to iOS versions other than those currently signed by Apple is not supported. Additionally, SHSH blobs are useless for downgrades.

What is Cryptex?

In iOS 16, Apple introduced a new firmware component known as Cryptex, which serves as a "virtual" co-processor. Its purpose is to enable Apple to deliver Rapid Security Responses (RSRs) independently from traditional iOS updates, allowing for faster installation. Similar to other firmwares, Cryptex has a signing ticket tied to a cryptographic nonce (number-used-once), commonly referred to as SHSH blobs. This means the firmware cannot be installed without a valid signing ticket and a matching nonce.

Apple's introduction of Cryptex creates compatibility challenges with older versions. Consequently, downgrading is typically impossible on non-checkm8 devices, except within patch versions (e.g., 16.3 to 16.3.1). Essentially, for A12 and later devices, downgrading is unfeasible, rendering it a dead end.

How to check SEP and Baseband compatibility?

Before attempting a downgrade, it's crucial to research whether the SEP and Baseband of the currently signed versions align with the version you intend to downgrade to. Failure to ensure compatibility could result in a failed downgrade, potentially rendering your device unusable (bricking), and necessitating an update to the latest iOS version, which may not be jailbreakable.

Refer to our article you can find a comprehensive list of compatible SEP and Baseband configurations for FutureRestore downgrades to the unsigned firmware version.

Written by

Kuba Pawlak

Kuba has over 20 years of experience in journalism, focusing on jailbreak since 2012. He has interviewed professionals from various companies. Besides journalism, Kuba specializes in video editing and drone flying. He studied IT at university before his writing career.

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