As suggested by Ryan, quoting his mail:

if after 3mins for searching for cdroms at /dev/hdc move on to the
next device, then the next if need be...and so on

if all devices fail print a message on the screen or fall back to
busybox shell (whice is what I get with out all-generic-ide)

if message is printed on the screen it should reference a boot
parameter for specifying the cdrom

IE: grml cdromsp=/dev/hdi (sp for search path)

to tell it where to look for the cdrom on boot