Lilo will not set "dos" as the default boot with a lilo.conf that reads
thus:

multiboot-$ cat /etc/lilo.conf
boot=/dev/hda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
default=linux
linear

other=/dev/hda1
        label=dos
        table=/dev/hda

image=/boot/vmlinuz.rds
        label=linux
        read-only
        root=/dev/hdb6

image=/boot/vmlinuz-2.2.12-20
        label=linux.orig
        initrd=/boot/initrd-2.2.12-20.img
        read-only
        root=/dev/hdb6

Manually booting selecting one boot or another during the delay seems to
work ok.