How is Apple X downgraded?

By querying SHSH, we can get the updated version of the current device, download the corresponding firmware, and do the up-sucking.

What is SHSH?

The full name of SHSH is Signature HaSH blobs, which is also called "signature certificate" at ordinary times. A certificate used to verify the legitimacy of iTunes when it resumes firmware operation.

When using iTunes to upgrade/restore the firmware, iTunes will submit the ECID to Apple's verification server and apply for SHSH to upgrade or restore the firmware of this system version. Apple will send a SHSH certificate corresponding to ECID to iTunes through the verification server, and iTunes can continue to upgrade or restore this version of firmware corresponding to this SHSH.

Simply put, SHSH is equivalent to a key, and you need to match the corresponding SHSH when swiping into an iOS version.

Matters needing attention

1. The currently available upgraded version can be obtained by querying SHSH, and all Apple's open verified iOS versions and devices can be supported (at present, Apple has officially turned off the verification of iOS 1 1.4 and below, and cannot downgrade to iOS 1 1.4 and below).

2. Make sure that the device has not turned on the function of finding my iPhone activation lock, or determine the Apple ID and password of the current device login, otherwise the device may not be activated after the brushing is completed.

3. Please back up important data before refreshing, or select "Refresh with user data" to prevent important data from being lost. If the operation is degraded, it is not recommended to check "Save user data to the brush machine", which may lead to brush machine failure or equipment abnormality. You can make classified backups through AISI Assistant and then operate. After successful brushing, the data can be classified and restored.

Introduction of "Professional Brush Machine" Interface

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

Query SHSH: You can query SHSH to get the information of iOS version that can be swiped.

Import Firmware: Import the firmware of the system version that needs to be refreshed.

Brush now: After importing the firmware, you need to click "Brush now" to brush.

Activate immediately: activate the equipment after the brushing is completed.

Keep user data and brush machine: you can check when you brush in iOS 7 and above, and the device data will not be lost after brushing, and the device does not need to be activated.

Do not allow baseband upgrade: only valid for "downgrade iPhone 4 or brush iOS 7 and below". In addition, it makes sense to reserve baseband only for devices with network lock. If the current device does not have a network lock, it does not matter whether the baseband is retained.

"Professional brush machine" operation steps

1. Connect the mobile phone to the AISI assistant on the PC side, click "Brush Prison Break"-"Professional Brush", and first select "Query SHSH" in the options on the right side of the current interface to get the system version that can be brushed into the current device.

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

2. Enter DFU mode according to the prompt;

Before iPhone 7/7P, this model entered DFU mode: press and hold the Home button of the device all the time, then press and hold the power button of the device until the screen of the device goes out, release the power button of the device after 4 seconds, but press and hold the Home button until the software prompts "Success", and then release the Home button. (For iPhone 7/7P, please use the Volume Down button instead of the Home button);

How to enter DFU mode for iPhone 8/8P/X: Press the volume up button and volume down button once quickly, and then press the power button all the time. After the device shuts down by itself, press and hold the volume reduction key for 5 seconds, and release the power button, but do not release the volume reduction key until the software prompts "Success".

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

3. After entering DFU mode, SHSH will be automatically queried to obtain printable information. Red indicates the version that cannot be swiped at present, and yellow indicates the system version that can be swiped.

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

4. After confirming the printable version of the current device, download the corresponding firmware from the "Firmware Download", and you can check the download progress and storage location in the "Download Center";

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

5. Wait for the firmware to be downloaded, return to the "Professional Brush" interface, click "Select Firmware" and select the downloaded firmware (if you can't determine the path, you can open the file location search in the "Download Center" in the upper right corner);

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

6. After selecting the firmware, click "Brush Machine Now". If it is not DFU mode at present, you need to enter DFU mode first (refer to the tutorial method in step 2), and the machine will automatically brush after entering DFU mode;

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

7. Wait for the brush machine to complete, as shown in the following figure, indicating that the brush machine is completed (the process takes about 10 minute);

How to downgrade iPhone X? | AISI Assistant Professional Brush Course

8. Wait for the phone to turn on, and click "Activate Now" (if you want to save data, you don't need to activate it), as shown in the figure, indicating that activation is complete.