Finally, verify your choice by clicking the "Update" button, then i Tunes will get to work downgrading your device's firmware.
The rest of the process will happen automatically, so sit back and wait (it will take up to 30 minutes), then your device will automatically reboot, and the old firmware version will be installed.
So head to the If you've experienced any bugs after downgrading with Method 1, it's likely because of corrupt, leftover data from the newer version of i OS.
The only way to solve these issues is to do a full restore and get rid of the corrupt data.
To start, connect your i OS device to your computer, then follow these steps: Just like with Method 1, i Tunes will take care of the rest, and your device will reboot after it's done.
Once the process has finished, run through initial setup, then select "Set Up as New" if you want a completely new start, or "Restore from i Cloud Backup" if you want to get all your apps and data back.
You could try backing up after trying Method 1, but some of the issues could still persist.i Cloud should have automatically created a backup when you were last running 9.3.5 before updating to i OS 10, so most folks will be fine.
So head to one of those sources on your Mac or PC, then select your device model to download i OS 9.3.5 for it.
Apple basically blacklists older firmware versions, so only the past version or two can be installed. Click the download link for the file you want and wait for it to download.
The file is rather large, so it could take up to 30 minutes to download, depending on your internet connection.
If going with the latter, just sign in with your Apple ID, then select the most recent i OS 9.3.x backup, and your apps and data will be restored.
If you choose this method over the easy one to begin with, make sure to see the step above about removing your beta profile if you no longer want it. Let us know below, and we'll try to steer you in the right direction.