During the development of my Linux From Scratch I were searching for a way to test the boot process using Virtual Box instead of rebooting my development computer again and again. I found some articles on how to achive this using Windows, but I use Linux on my computer. Finally I did it :) using VBoxManage internalcommands. As I found no articles on this, here comes a short howto:

When working with VirtualBox, sometimes its useful to clone a OS by just duplicate the *.vdi hard disk file and create a new OS with this hard drive. When you just copy and paste the .vdi file you'll get an error because the uuids of the partions on the already in use by VirtualBox. The correct way to do this is: