I didn't see this anywhere in the troubleshooting guide, perhaps mention of this should be added.
I had gotten done charging my Dingoo's batteries, and was going to plug into my computer now, to install some stuff...and the computer was not seeing anything.
Drive I (internal dingoo) and drive J (SD Card) were both showing up, but as BLANK....WIPED, utterly clean!
When I tried to boot into Dingux...froze on the Dingux screen - it would boot into normal mode
I recalled I had taken out my SD Card, just yesterday, to see what size the card was. So...I took it out again, and installed JUST the micro SD card into my card reader in the computer....EVERYTHING WAS THERE!!!
So, the first thing I did was make a backup of all essential files and folders. Then prayed.
I put my Micro SD back into the Mini SD adapter, and turned on. It worked. So I tried a boot into Dingux....IT WORKED!!
Bottom line...if you are freezing on dingux screen, and can't go on, - it is likely because it can't find the boot-files.
One of the REASONS it may not be able to find your bootfiles is because your SD Card is seated incorrectly, or badly in your adapter.
Try taking the Micro SD out of the Mini SD Adapter....and, into your card reader on your compy if you have one.
If not...just try putting the Micro SD back into the adapter...or even try a different adapter...and try again.
This has saved me from wrongly formatting and re-flashing my dingoo, and thus saved me from an incredible amount of work re-copying files.
The important lesson here is to always back up AS YOU ARE GOING...so that you don't lose anything. And try EVERYTHING...before going to the extreme of re-formatting/re-flashing.