Huge Oops!! Please forget my last, grandiloquent post about my
"investigation": it did not cross my mind that core.img was _already_
compressed with LZO, so the results are not fair to it. I will repeat
the test tomorrow with what could be a pseudo pre-compression core image
consisting of kernel.img, pc.mod, fshelp.mod and ext2.mod cat'ed
together, which should be similar enough to what grub-mkimage does.
Sorry for making everybody waste time (once again) due to my
short-sightedness... The worst part is that I digitally signed the last
message, so I cannot even deny I wrote it :-(