This is not how it should work. When you choose image you have started the last time, box should start without reboot (because it's not necessary to flash kernel).
Yes this is the usual way used in meoboot and OpenMultiboot . But i was thinking to have explained that this is not possible with OpenGL drivers, look at post #116.
Indeed with this procedure the bootmenu of original OpenMultiBoot return an error and the bootmenu is not shown.
For this reason we are trying to explore alternatives.
These are only tests to try to find an alternative way to have bootmenu working in that images too.