update-grub hangs

[Michael Sullivan <garuda@wi.rr.com>]

I'm trying to install a low-latency kernel and managed to get through 
the whole process, but when I ran update-grub, it finds my old kernels 
but not the new one. 

I added the new one by hand, copying the portion of menu.lst that 
specifies a kernel, changing the name, and copying the entire kernel 
line (but changing the version of vmlinuz to the new one)


here is the entry that works:

title        Libranet GNU/Linux, kernel 2.4.19
root        (hd1,0)
kernel        /boot/vmlinuz-2.4.19 root=/dev/hdf1 ro hdh=scsi hdg=scsi
savedefault

here is the one that doesn't work:

title        Low  latency GNU/Linux, kernel 2.4.24
root        (hd1,0)
kernel        /boot/vmlinuz-2.4.24 root=/dev/hdf1 ro hdh=scsi hdg=scsi
savedefault



When I tried to boot the new new kernel, I get a kernel panic with an 
error indicating that there was a problem with the root directory 
root=/dev/hdf1  but that is  root for the other kernels and they boot 
without a problem.

I then tried to run update-grub, and it sees the old kernels but not the 
new ones, and apparently hangs as the program never exits.

Any suggestions for someone new to making kernel changes?