Step 3. If there is no pop-up window, you can restore iPhone 8/8 Plus manually. Click "Summary" > "Restore iPhone". It will ask you to backup your iPhone. You can follow the guide to backup and restore your device. (If you have previous backup files on your computer, you can click "Restore Backup" to restore iPhone 8/8 Plus.)
6. Use Apple Phone Repair Tool If all the solutions fail to solve your problem, then here is another ultimate solution to fix iPhone 8 stuck on restart cycle without recovery. That is to repair the operating system without data loss. You can fix it through professional iOS repair tool, Apple phone repair tool only takes one click.
Step one: Download and open the iPhone repair tool, use a USB data cable to connect your iPhone to your computer, and click "Start".
Step 2: Select the repair mode, giving priority to "Standard Repair" to avoid losing device data.
Step 3: Click "Download Firmware" and start the repair after the download is successful. The entire repair process takes about 10 minutes. Be careful not to disconnect the data cable and wait until "Repair Completed" is displayed.
Part 2: How to Troubleshoot Hardware Issues, How to Repair iPhone 8/8 Plus 1. Charge iPhone at Proper Temperature Sometimes cold/hot weather can cause your iPhone to automatically restart. So you need to heat/cool the iPhone and then charge the iPhone to see if that solves the problem.
2. Replace the battery If all else fails, there may be a hardware issue. You can first check the battery condition yourself. Go to Settings > Battery, and if you see the message "iPhone battery may need service", go to the Apple Store and ask a staff member to replace the battery for you.
This is how to fix the problem of iPhone keeps restarting. Regardless of whether your iPhone 8/8 Plus is stuck in boot loop after jailbreaking or during iOS update, you can easily fix it using the above-mentioned solutions.