I've just finished building LFS on an external hard drive attached to my
laptop via a USB port.

My system recognizes the external drive as /dev/uba. I have put LFS on the
second partition of the drive, i.e., /dev/uba2 .

My problem: I'm now ready to configure and install Grub, but I need to know
how to set it up. One problem is that, after I finish getting everything
ready, I'm going to pull out my currently installed internal hard drive and
replace it with the one that I've built LFS on.

So, what is now /dev/uba will become /dev/hda.

In other words, what is presently an external USB hard drive will later become
an internal hard drive.

I *don't* want to write grub to the MBA or any partition of my currently
installed internal hard drive, as I use Lilo on that drive. Besides, that
drive won't be installed when I try to boot into LFS.

Any ideas? I'm poised to finish this three-day task, but I don't want to blow
it now!

Thanks.

Got it taken care of, thanks to Knoppix. I installed the external drive as my laptop's internal drive, then used Knoppix to get grub properly installed. The _Knoppix Hacks_ book that Santa Claus brought me has a good section on this.

Now I've got to figure out why my proc filesystem isn't mounting properly. But that's another story.

If you install a Linux in one disk-order position and then use it in another disk-order position you must amend all the partition references in /etc/fstab.

It original root partition must be amended to reflect the new environment.

Not a big deal just editing a couple of lines. I have moved partition from a Sata to an IDE and at different partition number. It is one of the nice bit of Linux that you can always move the distro from partition to partition, from disk to disk and from computer to computer.

Some of my distros were installed 2 PC before my current one.