If you include
(for the case of a 15MB compactflash, I don't know the geometry for larger
units) in your lilo command line, either manually at boot time or via
append = "hdb=noprobe hdb=477,2,32"
in your lilo.conf, then the kernel's hd driver will know to assume the
compactflash is there without bothering to probe for it. (Don't know
why lilo and the driver don't conspire to let you tell lilo to tell the
driver to try probing for it.)
The only gotcha is that the kernel panics if you give it this when the
compactflash is not installed, in which you need to either plan ahead by
reinstalling the loader with the append commented out just before
you remove the flash, or manually providing the command line without the
noprobe when booting without the flash.