by Ken Task.
It's more work, but safer I think. Think you've decided wisely.
/boot partition filled up ... well, you'll be happy to know that happens with all Linuxes. Most, if not all, keep a copy of previous old kernel.
Update to kernel is placed at the top of the list and it boots from that kernel. Doesn't remove the old kernel's however. Happend to me also on a CentOS server that had been 'around for a while'.
Was able to login via ssh and remove old kernels to recover space.
Lesson: pay attention to drive space usage! ;)
'spirit of sharing', Ken