in redhat you can make a boot disk with mkbootdisk. First determine what version of the kernel you have. Then use mkbootdisk

# uname -r
# mkbootdisk --device /dev/fd0 2.4.36-0.7

where 2.4.36-0.7 is the version number of your kernel as displayed with uname -r

you can also get the version number with

# cat /etc/lilo.conf