Hello.
What is the system version on your MD802?
The latest system version is V4.50. If it is not V4.50, please update it first.
After that, if the problem still persists, you can update format the SD card and then do the updates again.
By the way, when updating your MD802, which PC suite software version are you using?
We have released the new PC suite software version, V6.31, on our website. You can log in our website to download the latest one.