During the GitHub branch rename effort the previously public LTS branches in the `vyos/vyos-1x` repository were renamed from their original names (e.g. `circinus`, `sagitta`) to `circinus-public-unmaintained` and `sagitta-public-unmaintained` respectively. Additionally, the rolling branch was previously named current.
The build script clones `vyos-1x` to load the required Python modules for template rendering. It derives the branch name from the build defaults, relying on consistent branch naming between `vyos-build` and `vyos-1x`. The public repository renames broke this assumption, causing the clone step to fail for LTS builds.
Change the default `VYOS1X_REPO_URL` to point to the private `VyOS-Networks/vyos-1x` repository, where the original LTS branch names are preserved and maintained. The URL can still be overridden via the `VYOS1X_REPO_URL` environment variable for custom or local setups.
## Error
```
(11:03) vyos_bld f5b93e5fddc6:/vyos/vyos-build-circinus [liveboot] # isobuild -liveboot
Building custom VyOS version: 1.5-liveboot-202606281103
E: Could not retrieve vyos-1x from branch circinus: GitCommandError(['git', 'checkout', 'circinus'], 1, b"error: pathspec 'circinus' did not match any file(s) known to git", b'')
```