I have the identical setup as caxef6. It's a kingston 32GB C4 with a sansa clip + 4GB rockboxed to 3.13. My problem is similar.
The 32GB SD-card is known to the rockbox OS, but when i copy a larger number of files to it, only folders are shown and not the files and i get a error message from my OS saying the device is no longer there. Only a portion is been copied correct.
When i put the files on the external card directly without passing through the USB rockbox interface there are no errors, all files are there without error. When I insert the card in the rockbox not all files are shown. There are folders with no files... I have 75% flac files and the rest is 320mp3.
I checked the card with other devices, no problems.
I formatted the external card using the sandisk OS, also tried with a 64kb allocation size and the default size.
PS ROCKBOX ROCKS
