DFU mode FileSystem corrupted?!?

Hi, after a test of the gabonator custom firmware (search ds203 on GitHub, it’s the first project in the result list) (on an HW 2.81) I had an fpga error (probably for an incompatibility from the gabonator fw with the hw 2.81).
I have restored the original firmware and fpga without problems BUT with a strange effect.
Now when I connect the dso203 to the PC, in DFU mode, the filesystem shown is strange because contains some files/folder with strange characters (I think Chinese chars) and it is not possible to rename/delete them.
When I try to upload an additional app all seems working in the correct way except for the filenames with the srange chars.

There is a way to restore the original filesystem?

My current configuration is:
Hardware Ver 2.81
SYS Ver 1.64
APP (Plus A1) Ver 1.13