I did a second install of Leap 42.1 in a free partition (since the first one is
broken, see  bug 958798). After completion of the installation and reboot there
was only one entry for Leap 42.1, i.e. the new one. I had to edit grub.cfg to
be able to start the old (broken) installation. I don't know how to reach the
old snapshots, since the stanza in grub.cfg calls automatically the snapshots
of the new installation. There should be additional menu entries for both, old
installation and old snapshots or is it a feature masking double installations?