Qubes VM Kernel
- Follow the Qubes OS Installing kernel in Debian VM [archive] instructions.
- Ensure the Qubes VM kernel is functional before proceeding -- Qubes VM kernel issues should be raised at Qubes support [archive] and not in Whonix ™ forums.  
- Reboot dom0 with Qubes VM kernel. This is because Qubes VM kernel might break unrelated things such as the USB VM. 
- Once the Qubes VM kernel is functional, proceed with the following instructions.