If the original version of the system is lower than the system after brushing, then it's not possible.
If the original version of the system is the same as the system after brushing, then yes.
Apple phones can't be downgraded after flashing and upgrading.
Apple's statement that you can't downgrade after upgrading:
IOS adopts the upgrade strategy of recommending upgrades and enforcing keeping them up-to-date, and once upgraded, there is no possibility of downgrading.
The purpose of keeping the system version up-to-date is to prevent users from being exposed to vulnerabilities in lower versions.
Apple has introduced ID lock since IOS7, and the ban on downgrades is to prevent people from stealing and reusing them by downgrading, which can effectively reduce the rate of iPhone and iPad theft.
Apple phone brush is recommended to brush the official verification has not yet closed the system firmware.
Preparation before brushing with XY Apple Assistant:
Before brushing, you need to do a good job of backing up important data and information, and XY Brush Assistant provides a backup function.
Confirm whether you have turned on Apple ID lock (i.e. find my iPhone function), if so, please turn it off to prevent the activation of Apple ID password after brushing. How to turn it off: "Settings"-"iCloud"-"Find my iPhone" select Close.
XY Apple Assistant brushing tutorial:
Successfully connected to the device, click on the "one-key brush";
Enter the import or download firmware page, you can automatically match the version of the firmware can be brushed, click on the "start brushing" Click "Start Flashing" to start downloading the firmware, and then automatically enter the flashing process after the firmware is downloaded. If you have downloaded the firmware, you can directly "import firmware" to start brushing;
XY Brush Assistant takes about 5 minutes to brush, please wait patiently, do not disconnect the device or other operations;
After brushing, it automatically enters the activation process, and can be activated.