For a long time I was timid about rooting an Android device, fearing the complex procedure and the risk of ruining the device. I have finally done this today. But this is not without spending a lot of time sorting through the advices and free programs that suppose to do this. The few free programs I have vetted all looks like Trojan that are bundle with spyware.
Finally I have found the program from 刷机精灵官网-安卓(Android)一键刷机工具. It rooted the device effortlessly. As far as I can tell, it does not seem to carry any spyware. The UI is entirely Chinese though.
After it is rooted, I use the shell to disable Phone.apk and TelephonyProvider.apk. This stopped the "Cell Standby" function from eating up the battery. Which is absurd given the device has no 3G capability. This is the command I have ran
c:> adb shell # cd /system # mkdir app_backup # mv app/Phone.apk app_backup # mv app/TelephonyProvider.apk app_backup
After reboot, the cell standby row is removed completely.