9.1-STABLE zfsloader failure

[Roberto de Iriarte]

I have done some additional research on this,

The machine is a MacBook Pro 4,1, the firmware is only able to boot 
directly to HFS+ formatted GPT partitions. It is able to boot into MBR 
based partitions (which are labeled "Windows" regardless of type)

My disk layout is as follows

# /usr/local/sbin/gdisk /dev/ada0
GPT fdisk (gdisk) version 0.8.5

Partition table scan:
   MBR: protective
   BSD: not present
   APM: not present
   GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): p
Disk /dev/ada0: 625142448 sectors, 298.1 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 33EE1EC7-DF42-11E2-95A9-001CB3C56DFB
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 625142414
Partitions will be aligned on 8-sector boundaries
Total free space is 13 sectors (6.5 KiB)

Number  Start (sector)    End (sector)  Size       Code Name
    1              34             161   64.0 KiB    A501
    2             168        16777383   8.0 GiB     A502 swap0
    3        16777384       625142407   290.1 GiB   A504 disk0

Partition 1 contains the bootloader and is of type freebsd-boot
Partition 2 is of type freebsd-swap
Partition 3 is of type freebsd-zfs and contains the root filesystem

As described, and with the bootloader installed via

gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada0

My system is unable to boot by itself directly. It does boot with the 
help of refit or refind

With 9.1-RELEASE, it used to be possible to create an "Hybrid MBR" 
(http://www.rodsbooks.com/gdisk/hybrid.html) either with refit of gdisk, 
activate the MBR entry that points to the bootloader and have the system 
boot directly without refit or refind

With the new zfsloader from 9.1-STABLE, the system is still able to be 
booted from refit or refind, however, if i create the Hybrid MBR, the 
boot pwouldrocess stops with the message (twice)

ZFS: can't find pool by guid
ZFS: can't find pool by guid

And the install rendered unbootable, either directly or with refit/refind

Mounting the disk from a live CD and replacing /boot/zfsloader with the 
one from 9.1-RELEASE solves the problem (This means i cannot upgrade 
from ZFS v. 28 to the new feature flags spec ?)

I don't know if this behavior qualifies for a problem report ?

Thanks
Roberto