Cannot retrieve thumbnails from USB RNDIS

[ghost]

I'm playing with the HTTP requests via USB/ RNDIS and they seem to work fine. However I cannot retrieve any thumbnails of the videos. Example:

http://192.168.168.1/DCIM/100MEDIA/EYED0783.MOV?act=thm

return error 404 (not found). The file 0783 is available, I see it in the directory listing and changing the query to act=info leads to retrieve the information.

I have to do something further in order to get the cam producing the thumbnails?