amd64/160801: zfsboot on 8.2-RELEASE fails to boot from root-on-zfs in MBR slice

[Camillo Särs]

>Number:         160801
>Category:       amd64
>Synopsis:       zfsboot on 8.2-RELEASE fails to boot from root-on-zfs in MBR slice
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Sep 18 13:10:07 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Camillo Särs
>Release:        8.2-RELEASE
>Organization:
>Environment:
FreeBSD free 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Thu Feb 17 02:41:51 UTC 2011     root at mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
/boot/zfsboot when installed fails to boot from root-on-zfs in MBR slice, set up according to this:

<http://wiki.freebsd.org/RootOnZFS/ZFSBootPartition>

I upgraded from 8.1 to 8.2-RELEASE, and consequently upgraded my zfs root pool to version 15.  Upgraded the bootloader in Fixit prompt to allow booting from v15 pool.  After this, the system fails to boot, and freezes after the "Boot:  F1" prompt with "-" on the screen.  See this thread for example screenshot:

<http://forums.freebsd.org/showthread.php?t=22105>

MBR is used because of BIOS incompatibility with GPT as installed by FreeBSD.
>How-To-Repeat:
Set up root-on-ZFS in MBR slice on 8.2-RELEASE according to:

<http://wiki.freebsd.org/RootOnZFS/ZFSBootPartition>

Reboot - system halts on "-".
>Fix:
Install zfsboot from 9.0-BETA2, where the problem is fixed.

>Release-Note:
>Audit-Trail:
>Unformatted: