I have a triple-boot PC with Ubuntu 16.04, elementary OS Luna and WinXP with the first being the primary OS loaded upon startup. Everything worked very well. After running updates of eOS in the respective partition I ended up with i) GRUB starting eOS upon startup by default instead of Ubuntu and ii) about 8 entries for Ubuntu to choose from in the selection list of OSes available to start.
I know eOS Luna is a pretty old version, but for the moment I wanted to keep it.
Does anybody know i) what might be the reason for such effect and ii) how to fix it, i.e. make GRUB start U. by default and eliminate those extra entries?