Stupid me! Seems you need to alter the time out to 10s in order to select the VM option in the loader.... I didn't know it just auto selected the first line before I opened the VNC!   Step-by-step guide working for me: Create VM use CENTOS First scroll down make sure it's set to br0 Either copy MAC and edit synoboot.img , or edit MAC / SN after generation use OSFmount Copy edited synoboot.img to wanted location and set permissions to 7777 Host Passtrough (i'