Solaris X86 restore after replacing hard drive

I have a system with a DOS partition and a Solaris x86 2.5
partition. The original EIDE (2GB) hard drive failed and it
was replaced with a larger (4 GB) EIDE drive.

To restore the old partition I reinstalled Solaris from the
CDs. After the installation finished, I opened a cmdtool
window, mounted the filesystems (under the temporary /a
mount point used by the install program) and then restored
from tape using 'cpio'. The restore seemed to work fine.
Yet when attempting to boot from the Solaris partition, the
system can not mount any slices other than the root (0)
and fails with a message of the form:

  mount: /dev/dsk/c0d0s6 no such device

The device does exist. In fact, if I boot from the install
floppies I can mount /dev/dsk/c0d0s0 to /a and
/a/dev/dsk/c0d0s6 to /a/usr.
All files appear to be there but something is preventing a
proper boot. The Solaris boot menu does come up OK. Could
it be that one (or more) of the restored files have low
level disk geometry and/or sector information that needs
to be changed ?

Strangely enough, there is very little information on
access1.sun.com on disaster recovery. If anybody has a
suggestion, please send a cc to my email address
jalvarez@essnet.com).

Thanks in advance,
--Jesus Alvarez