I finally solve the problem.   It is the combination of the way things got
handled in readdisklabel() of disksubr.c and my harddisk.  My root is on Seagate
ST-1096N, which has 1 spare sector for each cylinder.  So the calculated
sector/cyl is alway 1 more than the specified sector/cyl value.  This ends up
causing the kernel to try to mount the root partition started at the wrong
sector.  Once I changed to use the specified value, the kernel boot up without
a problem.  And I found that most of the binary (bin-0319, I think) work with
the new kernel so I don't need to update the binary yet so I can revert back
to old kernel if there are other problem with the new kernel.

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        lp->d_secsize = rbp->nbytes;
        lp->d_nsectors = rbp->nsectors;
        lp->d_ntracks = rbp->nheads;
        lp->d_ncylinders = rbp->ncylinders;
>>>>    lp->d_secpercyl = lp->d_nsectors * lp->d_ntracks;   <<<< Original
>>>>    lp->d_secpercyl = rbp->secpercyl;                   <<<< New
#ifdef DIAGNOSTIC
        if (lp->d_secpercyl != rbp->secpercyl)
                printf("warning found rdb->secpercyl(%d) != "
                    "rdb->nsectors(%d) * rdb->nheads(%d)\n", rbp->secpercyl,
                    rbp->nsectors, rbp->nheads);
#endif
        lp->d_secperunit = lp->d_secpercyl * (rbp->highcyl - rbp->lowcyl + 1);
        lp->d_sparespercyl = lp->d_sparespertrack = 0;
------------------------------------------------------------------------------

I don't know what is the best way to handle this problem in gerenal.  It seems
that lp->d_sparespercyl is intended for this.  But I don't think we can specify
this in the Amiga rigid block.

Song.

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