Hello. Same here, I even tried to put the MAC of my dead 209+ with no luck. I'm using XPEnology on VirtualBox, the good mac is shown in ifconfig -a. EDIT: There files: ls -l /proc/sys/kernel/syno_mac_address* are empty. Maybe some tools uses sysctl to check the MAC, and fail because of this. Can someone with a working Synology NAS can check?