Booting a USB Stick in VirtualBox with a Mac OS X Host
Published on December 30, 2013.You can't just boot from a USB Stick with VirtualBox because it's BIOS does not support USB.
However, you can still get it to boot from USB.
But first, you have to convince OS X not to remount your USB Stick everytime it's /dev/diskX file is accessed.
To do this, you need to know the Label of your USB drive (with spaces escaped with \) and it's filesystem type (fat32 in this case).
Create the /etc/fstab file, if it doesn't exist already, and mark your stick as noauto:
sudo touch /etc/fstab sudo nano /etc/fstab LABEL=yourUSBstick none fat32 rw,noauto
Then create a VirtualBox Disk Image, pointing to the block device file of your USB stick. Use diskutil to find out the device file name.
diskutil list sudo VBoxManage internalcommands createrawvmdk -filename rawUsbStick.vmdk -rawdisk /dev/diskX
Now, run VirtualBox as root
sudo /Applications/VirtualBox.app/Contents/MacOS/VirtualBox
Create a new Virtual Machine, using the .vmdk file created before as virtual hard disk drive. Boot it, and...
Done! :)