By default, the Qubes installation media only supports creating the core sys-* qubes derived from "full" Templates. :woozy_face:

Which for many users choosing Qubes OS for it's security & privacy efforts ...

https://64.media.tumblr.com/9a3addb0d200b6e96da08fb9119ff05b/tumblr_mjiowhyrJs1s2b58zo2_400.gif

Here is a simple bash solution:

https://github.com/cayc3/sys-swap

TL;DR:

1. Create TemplateVM + AppVM (Template for disposable) for each 'sys-*' qubes
2. Shutdown 'sys-*' qubes
3. Backup existing 'sys-*' qubes
4. Remove existing 'sys-*' qubes
5. Salt new 'sys-*' qubes based on desired TemplateVM

[details="Note about driver selection:"] For sys-net, be sure to replace firmware-iwlwifi in the script with appropriate drivers for system used. [/details]

Disclaimer:

IMO, "rebuilding" a Qubes install with only dom0 + a single functional TemplateVM ought be within any Qubes operator's abilities.

If unable to read/understand this basic script, DO NOT USE as, there is a good chance failure to run successfully can lead to a system which feels unusable (not actually the case) and some novice users may feel as though a reinstall is necessary.