Using the MD9781 MP3-player with Linux

In December 2002 a large German trade chain sold this portable MP3-player for a very good price. Since I use Linux I looked for a driver to upload and download files to the player. But the device uses a vendor specific protocol so none of the existing drivers worked. So I decided to write my own...

Medion sells the player with 64MB internal memory by the name "MD-9781 Tragbarer MP3-Player-/Recorder". PoGo Products sells the device by the name "RipFlash PLUS" http://www.pogoproducts.com/ripflash_plus.html Their player has more memory (128MB) but the Medion player costs only half. :-)

The USB vendor ID of the device is 0x4e8 that means the chip is from Samsung. The product ID is 0x1003.

I have analysed the protocol used for communication with the player and wrote my own program "md9781-manager" that implements the most important parts of the protocol:

• list the files on the player
• delete a file from the player
• upload a file to the player
• download a file from the player - btw: the manual says that's impossible... ;-)

Installation

To use the md9781-manager you need a kernel with USB support configured. A simple check (with the device plugged in):

grep Vendor /proc/bus/usb/devices

You should see a line that begins with Vendor=04e8.

You also need the libusb shared library. Most distributions already include it. If you do not have it it can be found at http://libusb.sourceforge.net/download.html

If everything works installing the program should be as easy as:

git clone https://github.com/jze/md9781-manager.git
cd md9781-manager/
./configure
make
make install   # (optional - this copies the md9781-manager binary to /usr/local/bin/ )

The access rights for the usb device file (/prc/bus/usb/001/xxx) are a little bit tricky. Usually only root is allowed to write to the file. There are several ways to solve this problem:

• run md9781-manager as root - bad
• have the line usbdevfs /proc/bus/usb usbdevfs devmode=0666 0 0 in /etc/fstab - also bad (now every user on the system can write to any file in the proc usb tree
• try this little skript and let the hotplug daemon do the work

#!/bin/sh
#
# /etc/hotplug/usb/md9781
#
chgrp users $DEVICE
chmod g+w $DEVICE

You will have to add the line

md9781 0x0003 0x04e8 0x1003 0x0000 0x0000 0x00 0x00 0x00 0x00 0x00 0x00 0x00000000

to /etc/hotplub/usb.usermap to tell the hotplug daemon to call the skript (don't forget to make it executeable).

Usage

Now give it a shot: md9781-manager -l You should see a list of all files in the players internal memory.

Some examples how to use md9781-manager:

The "-e" option tells the program to use the external smartmedia card of the player. List of all files on the card: md9781-manager -e -d

To delete the second file from the player: md9781-manager -d 2

Delete the third track from the smartmedia card: md9781-manager -e -d 3

Put a song to the player: md9781-manager -p my_song.mp3. The player uses a FAT file system so the filename will be truncated after the first 8 characters. If you want the file on the player of have a different name (i.e. to avoid ambiguous names) use md9781-manager -p my_song.mp3 other.

To get the first file from the player: md9781-manager -g 1 . This will save the file in the current directory. It will be called like it was on the player.

Dietrich Rothe (dietrich@d-rothe.de) send me a patch that make the usage of the program easier:

1. with -p you can upload multiple files
2. -d and -g accept a range-list with multiple numbers: for example

-d -3,4,20-40,49- deletes files 1,2,3, file #4, 20 to 40, and all files having a number greater than (including) 49 

The newest version of this text can be found at: https://github.com/jze/md9781-manager