That article on user wiki has been outdated for quite some time, schnapps actually has been rewritten to accommodate for changed root partition automatically, also the configuration has been moved under UCI (/etc/config/schnapps)
Btw, I think your solution with changing those two variables is by far one of the simplest. What I did personally was a bit more involved, inspired by these two posts on the forum:
- use of
UUID, so that I don’t have to worry when I add another disk: [SOLVED] - Extroot - (expanding Turris package space) - #32 by mina86 - Turris Omnia - Turris forum - modify the
bootcmdvariable so that I could reboot betweenscsi0and internalmmc0using the rescue button on the back: [SOLVED] - Extroot - (expanding Turris package space) - #18 by adminX - Turris Omnia - Turris forum