freebsd stable - Jan 2013 - Unable to upgrade ZFS pool to feature flags, SPA version 5000, on stable/9 @ r243825

Hi,

I installed FreeBSD/amd64 9.1-RELEASE yesterday.
I chose to do a manual installation due to the use of ZFS.
I checked out stable/9 and recompiled both world and GENERIC kernel.
Said kernel and world was installed without any problems.
System is still up & running, with uname -a revealing r243825.

I then decided to upgrade the root pool to feature flags, SPA version 
5000, and was not so lucky.

# zpool upgrade -a
This system supports ZFS pool feature flags.

cannot upgrade 'zroot': invalid argument for this pool operation

Even the command:

zpool upgrade zroot

gives the same diagnostic as above.

This isn't a critical system at all, but I guess everyone else will 
run into this snag when attempting to upgrade their ZFS pools.

Any clues?

-- 
+-------------------------------+------------------------------------+
| Vennlig hilsen,               | Best regards,                      |
| Trond Endrest?l,              | Trond Endrest?l,                   |
| IT-ansvarlig,                 | System administrator,              |
| Fagskolen Innlandet,          | Gj?vik Technical College, Norway,  |
| tlf. mob.   952 62 567,       | Cellular...: +47 952 62 567,       |
| sentralbord 61 14 54 00.      | Switchboard: +47 61 14 54 00.      |
+-------------------------------+------------------------------------+

On Fri, 18 Jan 2013 09:20+0100, Trond Endrest?l wrote:
> I then decided to upgrade the root pool to feature flags, SPA version 
> 5000, and was not so lucky.
> 
> # zpool upgrade -a
> This system supports ZFS pool feature flags.
> 
> cannot upgrade 'zroot': invalid argument for this pool operation
Pilot error.
For some reason I was still running the 9.1-RELEASE kernel.

Now the system happily runs 9.1-STABLE @ r245552.
Sorry for the noise.

-- 
+-------------------------------+------------------------------------+
| Vennlig hilsen,               | Best regards,                      |
| Trond Endrest?l,              | Trond Endrest?l,                   |
| IT-ansvarlig,                 | System administrator,              |
| Fagskolen Innlandet,          | Gj?vik Technical College, Norway,  |
| tlf. mob.   952 62 567,       | Cellular...: +47 952 62 567,       |
| sentralbord 61 14 54 00.      | Switchboard: +47 61 14 54 00.      |
+-------------------------------+------------------------------------+