These lines/script will snap back all branches back to the default master branch from the console:
cd /zynthian/zynthian-webconf/
systemctl stop zynthian-webconf
git checkout master
systemctl start zynthian-webconf
cd /zynthian/zynthian-ui/
systemctl stop zynthian
git checkout master
systemctl start zynthian
cd /zynthian/zynthian-sys/
git checkout master
cd /zynthian/zynthian-data/
git checkout master
cd /zynthian/zyncoder/
git checkout master
save it in a file on the zynthian if you like, and as long as you’ll be able to ssh to the zynthian you can revert all repositories back to their default master branch.
Then, experiment in safety 