It was answered long long time ago by @miska in “Turris OS 4.0 (Here be dragons) - Community office - Turris forum”
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Backing up your current setup on OmniaTo backup your current setup and your working configuration you would need a flash drive, preferably with ext4. Insert it into USB port and mount it. For example:
mkdir /mnt/backup; mount /dev/sdg1 /mnt/backup
Now you can use
schnapps
to backup your current system:$ schnapps create pre-4.0 backup Snapshot number 166 created $ schnapps export 166 /mnt/backup
This way you just created a medkit on your flash drive with your current setup. Any time you want to return to this working configuration just plug the flash drive into your router and perform 4 LEDs factory reset.
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Later is was repeated in “[solved] Medkit built from my Turris Omnia? - SW help - Turris forum” by @JardaB in slightly modified form
Does work in MOX as Well