FreeBSD 8.2 (stable) never boots successfully after installkernel/installworld

[Lars Kellogg-Stedman]

Hello list,

I've been having a recurring problem with my FreeBSD 8.2 stable
system: after going through the whole
buildworld/buildkernel/installkernel/reboot/mergemaster/installworld/mergemaster
process, the system no longer boots successfully: the loader reports,
"Can't work out which disk we are booting from".  It looks to my eyes
like the "zfsloader" binary is not getting built correctly: I've been
carrying around an older zfsloader in /boot, so that if at the boot
prompt I type:

  /boot/zfsloader.working

Everything works out fine.

The complete output of the boot process is here:

  https://twitter.com/#!/larsks/status/148191554278928384/photo/1

Additional details:

- This is FreeBSD 8.2 STABLE on amd64
- The kernel (and world) are current as of this afternoon
- This has only ZFS filesystems

This has been a very frustrating problem, and I'm not sure how to
start debugging things.  I'd appreciate your help.

Thanks,

-- Lars