I have an older machine that I originally set up as a dual boot with Windows 7 and Lubuntu. Part of that setup was establishing a small partition for /boot. The partition is 89 MB, and with recent changes in the initrd it's too small to support upgrading even though I only have the most recent kernel version in there (the updater wants 41 MB of free space, but I have only 40 and it's as stripped down as I can get it).
What I'd like to do is to just abandon the 89MB partition to the dustbin of bad ideas and move /boot into the root partition, where there is ample space. I don't want to mess with the partition layout on the disk, and I don't want to reinstall anything unless there is no other way.
So my question is, what is the easiest, least likely to cause downtime way to switch away from using a separate partition for /boot?