I had the same problem on my Teclast F7. I use Linux, and every time i use it in a while the system freezes getting hard disk errors in sda. When boot the EFI entry has disappeared and need to enter system using efi shell. In my case I solved the problem by simply inserting a piece of folded paper into the hard drive compartiment to avoid it can be moved. For the moment i have some time without errors 😀
