My 10.04 system (OS-1) got into a tangle the other day, so I installed a second, dual-boot 10.04 (OS-2), so that I could trouble-shoot the hung system...
In case it is relevant to my question, I'll mention that since I got OS-1 working again, it has shown a few battle wounds from its ordeal (.. actually the ordeal was mine ... trying to figure it all out ;) ... I lost some custom settings, but not all.
(For the curious: the hangup was caused by rsync writing 600 GB to OS-1's 320 GB drive.. The destination drive was unmounted at the time, and rsync dutifully wrote directly to /media/usb_back; filling it to capacity... I have since, ammended my script :)
Because the dual-boot MBR was prepared by OS-2, it is first on the grub list.. However, I want OS-1 to be the default OS to boot...
From OS-1, I tried two methods to change the grub-menu's defaule OS. eg.
Directly editing /etc/default/grub (then update-grub)
Running 'Startup Manager' (then update-grub)
Neither of these methods had any effect... so I started OS-2, and tried method 1... It worked!
Why can I not change the grub menu from OS-1? .. or if it can be done, How?