So, how did I solve this problem at last? iOS System Recovery, which is a software, was recommended to me by my friend whose job is to repair the abnormal iOS system. The software helped me to solve the problem and I also recommend it to you, because it really can help you kick out your iPhone and iPad from recovery mode or recovery loop. Well, to recover your device, please read below steps and follow it carefully.
Steps to Fix iPhone iPad Stuck in Recovery Mode/Recovery Loop
Step 1. Run iOS System Recovery and Connect Your Device
After you install iOS System Recovery and it runs normally. Connect your device to computer and choose "More Tools" mode on the left side of the window. Then click "Start".
Step 2. Recognize Your System and Choose a Right One
Now the program will identify your device's system, if it fail, don't worry, you can select the right version manually. "How to check the device model?" can help you know your right system model. Selected it and click "Download" button to keep the process continue.
Step 3. Repair and Fix Your Device
When the program download the latest system for your device, it will begin to repair your device directly. Please be patient, and keep your device connectting the computer, or it could be a "brick". The repair process will last for a short while. And at the end of it, it will remind show you "Repair operating system is done".
It's not very difficult, isn't it? iOS System Recovery can not only be used to fix your system, but also can be used to restore deleted or lost data from iDevices, back up data, transfer WhatsApp from iDevice to iDevice or Android. So, I think it will help you in many ways.