ZFS root BTX Loader very slow

[Gianni]

I've installed root on ZFS according to the Wiki.
http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/Mirror

I rebuilt world yesterday and upgraded my zfs pool to version 14 and also upgraded the bootcode with:
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ad4
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ad8

Now on boot the system waits for about 70 seconds at the following screen:

BTX Loader 1.00 BTX version is 1.02
Consoles: internal video/keyboard
BIOS drive A: is disk0
BIOS drive C: is disk1
BIOS drive D: is disk2
BIOS drive E: is disk3
BIOS drive F: is disk4
BIOS drive G: is disk5
_

No errors appear and eventually the system boots normally from the zfs root.
Any ideas why it's taking so long at this stage? what is actually going on at this point?

Thanks
Gianni