Today I had to reinstall my gateway/firewall but I no longer had blank CD’s.

I usually prefer to use a USB key but the asg-9.x.iso from Sophos has some issues with this.
I fixed it in a few minutes by comparing the mounts in a VM when booting from an ISO and the mounts when booting from USB.

The problem is that the installer only tries to mount the cd rom and not USB keys to /install.

  1. download the iso
  2. download rufus usb tool
  3. write the iso to the USB using rufus
  4. boot from the usb key
  5. hit return to start the installer
  6. hit ALT+F2
  7. find the device name for your usb key (dmesg | grep sd)
  8. mount the usb on /install (mount /dev/sdb1 /install)
  9. hit ALT+F1 to return to the install
  10. installer will now work

Hopefully this is useful.