thanks for your reply.

The logging is hardcoded (I think it was loglevel 11) by the owncloud developers in a file named like csyncthread.cpp. This could be made configurable, I guess they will fix it in one of the next versions.

Syncing subdirs should work with the right url for owncloudcmd, but I don't know which url Maybe have a look at the owncloud forum and post the solution here.

There are two major errors at the moment which are to be analyzed, but I don't have time atm due to our newborn twins.
1. Sometimes, files are immediately synced back which, I guess, is due to bad FAT accuracy. I made several tries to fix this but there are multiple places where file times are compared and I did not find all until now. This seems to be no maemo-specific bug. Luckily, the server recognizes the file as unchanged and does not distribute it further.
2. Worse: When a large file is uploaded (e.g. during the false back-sync), the last chunk is not transmitted correctly. To me, it seems like a memory leak but I could not find it. This problem is maemo-specific. Luckily, during the next attempt, only the last chunk is transferred and this time correctly, so owncloudcmd repairs its mistake.
If anyone would like to resolve these issues, I would be happy to integrate patches (the source code to the packages is uploaded to the deb system)!