Comment # 3 on bug 1023618 from Frans Leerink

Yesterday evening I updated the tumbleweed system (approx 500 updates) and shut
the system down as soon as the system reported that the updates are installed
successfully.

This morning again all other boot options,like windows 7 and opensuse-Leap, are
not available in boot menu. This happens regularly, but not always, after an
update.

I have corrected this situation by running Yast/system/bootloader without any
new input.