So I got a Sony Xperia Tablet SGPT121US and an Android Dell Venue 8, and they all get the same problem: boot loop stuck on logo screen. I have tried to at least factory reset and wipe data on the Sony (which run Android 4.0) through the Recovery mode but to no avail, the same thing keep appearing. For the Dell one, there are some data I wanna recover from it so I am still reluctant to reset it, and also I want to try everything out on the Sony tablet first. I have read up a few online posts from various place and I want to give them all a try, as long as I can revive them without bringing them to a service store. The thing is, I am not too god in this field of troubleshooting dead tablets. I've heard of methods like flashing or reinstall the OS and such, but I would need assistance for that (I don't even know what files/.iso are compatible for my devices to reinstall Android... Thank you!