I'm curious what happens when you plug it up with a standard usb mini cable?
Are you getting an error message? Or nothing?
I have never been able to get my 50H to work on any other cable.... until today. ?? I don't know.
Usually when I have trouble uploading with my 50H or 50F, it is resolved by changing the sequence.
You might try:
Disconnect all other usb devices, reboot, connect oximeter in menu mode, set to highlight upload, open spo2 review, click the "new session" magnifying glass, "new session" should be selected, click OK, should say "device connected, waiting for data", press & hold "upload", should say "recieving data..."