I got the firmware from
http://www.mydigit.cn/read.php?tid-20272.html.
Now my player starts up but when I try choose Music or Video from the menu I get this message: "disk error!".
I've tried formatting and doing the hack removal, but no success. The strange thing is that I now got two new drives, the normal USB-drive and an ACTIONS USB DISK CD ROM USB Device!
Does anyone have an idea what I should do now?