Difference between revisions of "Firmware downgrading"

From The iPhone Wiki
Jump to: navigation, search
m (Reason for downgrading)
 
(6 intermediate revisions by 5 users not shown)
Line 1: Line 1:
Downgrading is the process of restoring to an older [[firmware]]. Apple does not allow downgrading unless the firmware is being signed. Downgrading is only possible on [[S5L8930|A4]] or older devices that have [[bootrom]] exploits such as [[Limera1n]] with the exception of iPhone 4s that can be restored from 5.x to 5.x as long as there are valid [[SHSH]] blobs saved for both the iOS the device is on and the one the user wants to get. It is also possible to downgrade an [[iPad 2]] to 5.x with 4.x and 5.x SHSH or 4.x with only 4.x SHSH blobs. iPhone 4s and iPad 2 downgrading will require [[redsn0w]].
+
Downgrading is the process of restoring to an older [[firmware]]. Apple does not allow downgrading unless the firmware is being signed. Previously, downgrading was only possible on older devices that have SHSHs saved and are vulnerable to [[bootrom]] exploits such as the [[limera1n Exploit]]. However, it has become possible to downgrade devices with no (known) bootrom exploits to certain firmware versions, such as remaining on iOS 5.x or downgrading to iOS 6.1.3. It is also possible to downgrade an [[iPad 2]] to 5.x with 4.x and 5.x SHSH or 4.x with only 4.x SHSH blobs. iPhone 4s and iPad 2 downgrading will require [[redsn0w]]. [[Odysseus]] can be used on some devices to downgrade to certain iOS versions providing the user has SHSH blobs and the device is jailbroken. OdysseusOTA can be used to downgrade an iPhone 4s or iPad 2 to 6.1.3 from any firmware providing the device is jailbroken even without SHSH blobs due to Apple not closing the signing of 6.1.3 OTA's for those devices. [https://www.youtube.com/watch?v=fh0tB6fp0Sc&feature=youtu.be&a OdysseusOTA2] can be used to downgrade an iPhone5,2 to 8.4.1 the same way that OdysseusOTA did with iPhone 4s and iPad 2.
   
 
== Reason for downgrading ==
 
== Reason for downgrading ==
Some users downgrade since iOS 7 does not run as people want on older devices like the iPhone 4. This can also be for nostalgia. There's many reasons to why one would want an older iOS.
+
Some users downgrade to older iOS versions since, for example, iOS 7.x does not run as well as older versions on outdated devices such as the iPhone 4, or iOS 9.x on the iPhone 4S. This could also be for nostalgia. There are many reasons as to why one would prefer an older version of iOS.
   
 
==Restoring to Older Firmwares via Any Method==
 
==Restoring to Older Firmwares via Any Method==

Latest revision as of 10:45, 27 September 2021

Downgrading is the process of restoring to an older firmware. Apple does not allow downgrading unless the firmware is being signed. Previously, downgrading was only possible on older devices that have SHSHs saved and are vulnerable to bootrom exploits such as the limera1n Exploit. However, it has become possible to downgrade devices with no (known) bootrom exploits to certain firmware versions, such as remaining on iOS 5.x or downgrading to iOS 6.1.3. It is also possible to downgrade an iPad 2 to 5.x with 4.x and 5.x SHSH or 4.x with only 4.x SHSH blobs. iPhone 4s and iPad 2 downgrading will require redsn0w. Odysseus can be used on some devices to downgrade to certain iOS versions providing the user has SHSH blobs and the device is jailbroken. OdysseusOTA can be used to downgrade an iPhone 4s or iPad 2 to 6.1.3 from any firmware providing the device is jailbroken even without SHSH blobs due to Apple not closing the signing of 6.1.3 OTA's for those devices. OdysseusOTA2 can be used to downgrade an iPhone5,2 to 8.4.1 the same way that OdysseusOTA did with iPhone 4s and iPad 2.

Reason for downgrading

Some users downgrade to older iOS versions since, for example, iOS 7.x does not run as well as older versions on outdated devices such as the iPhone 4, or iOS 9.x on the iPhone 4S. This could also be for nostalgia. There are many reasons as to why one would prefer an older version of iOS.

Restoring to Older Firmwares via Any Method

Downgrade iTunes to 11.0 or 10.7 and then restore when in PwnDFU.