rescue grub -- help!

[David Liontooth <liontooth@cogweb.net>]

I cloned a drive, starting with the MBR:

 dd if=/dev/hda of=/dev/hdc  bs=446 count=1

However, after installing the cloned drive in the new machine, all I get
is a scrolling GRUB filling the screen. I downloaded an amd64 netboot 
CD, mounted / and /boot in /target, and issued

   chroot /target

Everything in there works fine -- the applications run. (I'm sitting at
another computer at this point with remote access to the installer). But
what I was counting on working, namely

   grub-install  /dev/hda

which used to work on i386, maybe a year or two ago, now gives me
"/dev/hda: Not found or not a block device." If I do df, chroot sees
only this:

   Filesystem           1K-blocks      Used Available Use% Mounted on
sysfs                  7740384   3197252   4149944  44% /sys
df: `/dev/pts': No such file or directory
tmpfs                  7740384   3197252   4149944  44% /dev

In the installer shell, I get

~ # df
Filesystem           1k-blocks      Used Available Use% Mounted on
tmpfs                   102400     30248     72152  30% /
/dev/cdroms/cdrom0       86390     86390         0 100% /cdrom
/dev/ide/host0/bus0/target0/lun0/part2  7740384   3197252   4149944  44%
/target
/dev/ide/host0/bus0/target0/lun0/part1    97826      9736     82871  11%
/target/boot

So it's using devfs, which I thought was deprecated? What do I tell
grub-installer?

When I chrooted to /target, it rewrote /etc/fstab (why?), like this:

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
/dev/hda2       /               ext3    defaults,errors=remount-ro 0       1
/dev/hda1       /boot           ext3    defaults        0       2
/dev/hda5       none            swap    sw              0       0
/dev/hdc        /media/cdrom0   iso9660 ro,user,noauto  0       0

In dmesg, I get

NFORCE3-250: 0000:00:08.0 (rev a2) UDMA133 controller
   ide0: BM-DMA at 0xf000-0xf007, BIOS settings: hda:DMA, hdb:DMA
   ide1: BM-DMA at 0xf008-0xf00f, BIOS settings: hdc:DMA, hdd:DMA
klogd[245]: segfault at 000000000000003e rip 0000002a9568b94e rsp
0000007fbfffe2a0 error 6
hda: WDC WD800BB-75CAA0, ATA DISK drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hdc: HITACHI DVD-ROM GD-7000, ATAPI CD/DVD-ROM drive

Obviously /dev/hda is seen, since the chroot is running on it.

What can I do? All I want is to rewrite the MBR, the installation itself
is fine.

Dave