The starting point is a fully operational RH 5.1, OS/2 Warp
3, Windows 98 and DOS system setup according to the
published HOWTO. RH6.1 product was purchased for an upgrade
to a more recent kernel.

The following occurred in order.

1) Upgrade "from the box" failed recognizing the hda6
partition (HPFS) in "plain vanilla" and "text" modes.

boot:
boot: text

2) Accessed the RH support area and downloaded new boot disk
image (boot-RHEA-1999_044.img) and update
(updates-RHEA-1999_045.img). Made the floppys and retried
the installation procedure with a 1999_044 boot. This time,
the install failed accessing the cdrom (the CDROM started to
spin but the install hung at this point). Retried the
install with the following boot options:

boot: linux updates cdrom=hdc text
boot: linux cdrom=hdc updates text

in both of the above cases, the CDROM drive still is not
recognized.

When the following options are used:

boot: linux update cdrom=hdc text

the CDROM is recognized but the upgrade fails as originally

Error mounting ext2 filesystem on hda6: Invalid argument

Traceback
File "usr/bin/anaconda", line 225 in ?
	intf.run(todo, test = test)
File
"../../../RedHat/instimage/usr/lib/python1.5/site-packages/text.py",
line 1000, in run
	rc=apply (step[1](), step[2])
File
"../../../Redhat/instimage/usr/lib/python1.5.site-packages/text.py",
line 222, in __call__
	parts=toto.upgradeFindRoot ()
File
"../../../RedHat/instimage/usr/lib/python1.5/site-packages/todo.py",
line 1130, in upgradeFindRoot
	isys.umount('/mnt/sysimage')
File "/usr/lib/python1.5/site-packages/isys.py", line 8, in
umount
	return _isys.umount(what)
SystemError: (22, 'Invalid argument')

Note that it has NEVER before been necessary to use the
hdc=cdrom option on this system. The cdrom (Secondary
master) is a relatively modern EIDE drive (Newcom 32x).
The rest of entire system is also hardware up to date.