Here's how you can downgrade iOS 11.2 Beta to the currently signed public firmware - iOS 11.0.3, iOS 11.0.2 and iOS 11.0.1.
Complete Tutorial on How to Downgrade iOS 11.2 Beta Back to iOS 11.0.1 - 11.0.3.
The first ever beta of iOS 11.2 is out now and developers can install it straight away. But of course, since this is beta software, therefore do not expect high-end performance from it in any way. In fact, it might not even fare well when it comes to battery life as well. So, if you are hitting a concrete wall over and over again then it might be wise to downgrade iOS 11.2 Beta back to the currently signed public release, which happens to be iOS 11.0.1, iOS 11.0.2 and iOS 11.0.3.
Before we begin, it's important to know that the downgrade process will wipe everything off your device. This includes your apps, settings, photos, etc. So, it would be wise to take a complete backup of your device either using iTunes or iCloud. Which route you choose is ultimately up to you as long as your data is well protected. Once that is out of the way, follow the steps below for downgrading your device.
Download the Firmware File.
Choose the firmware you wish to downgrade to. Your options are as follows.
Make Sure Everything is Backed Up.
I said it before and I'll say it again - please make sure you've backed up everything to iCloud or iTunes. You will lose everything at the end of the downgrade process.
Launch iTunes and Connect Your Device Using a Lightning Cable.
If you haven't already, download iTunes from apple.com/itunes and connect your iOS device to your computer using a Lightning cable.
Downgrade iOS 11.2 Beta.
Simply select your device from the top left corner of iTunes, click on the Restore iPhone button while holding down the left Shift key (Windows) or the left Option key (Mac). Select the firmware file you wish to downgrade to and let iTunes verify and restore your firmware and device.
Once the restore process is complete, you can set up your device as you normally would or restore from the backup you created prior to everything.
