>Number:         6954
>Category:       port-i386
>Synopsis:       /usr/mdec/mbr does not always work
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    port-i386-maintainer (NetBSD/i386 Portmaster)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Feb  6 15:20:00 1999
>Last-Modified:
>Originator:     Havard Eidnes
>Organization:
	RUNIT AS
>Release:        NetBSD-current 19990131
>Environment:
NetBSD vever.runit.sintef.no 1.3I NetBSD 1.3I (GENERIC) #1: Mon Feb  1 00:18:40 MET 1999     he@hugin.runit.sintef.no:/usr/src/sys/arch/i386/compile/GENERIC i386

>Description:
	I recently used sysinst to partition and install on a 10.1GB
	disk (after initial manual labeling).

	After installation, the BIOS (I think it's the BIOS) told me
	"Invalid system disk; Replace the disk and then press any key"
	The machine is a Dell Optiplex GXa, with "PHOENIX ROM BIOS
	PLUS version 1.10 A06".

	I installed the system on the second disk on the system, and
	used os-bs on the first disk to switch, but as I now have a
	fix for the problem those factors are not really part of the
	problem as far as I can tell.

	(Some may wonder how I used sysinst to install, and to tell
	the truth I used sysinst from an unannounced Jan5 snapshot to
	install the Jan31 snapshot, but the /usr/mdec/mbr code from
	Jan31 also fails, as evidenced from doing (NetBSD) "fdisk -i
	wd1" after trying the initial MBR.)

>How-To-Repeat:
	Try to use /usr/mdec/mbr on a machine as above, and watch the
	boot fail.

>Fix:
	Boot an MS-DOS diskette with fdisk on it.
	Reinstall a working MBR (in my case on disk 2) with

		fdisk /mbr 2

	The system now correctly boots as it should.

	I don't really know how to fix /usr/mdec/mbr, as I don't know
	what this particular BIOS looks for in order to detect whether
	a disk contains an MBR or not.
>Audit-Trail:
>Unformatted: