On NCP3 RC2, I get the error message Unsupported command. Please use 'apt-clone' command instead. when update_grub is trying to execute /sbin/bootadm update-menu.

Full log on a machine with ZFS mirrored syspool:

root@srv:/# sh -x /boot/solaris/bin/update_grub
+ PATH=/usr/bin:/usr/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin
+ export PATH
+ ALT_ROOT=
+ getopts R: OPT
++ uname -p
+ ARCH=i386
+ is_pcfs_boot=yes
+ is_zfs_boot=no
+ '[' -f /platform/i86pc/multiboot -a i386 = i386 ']'
+ check_pcfs_boot
++ grep -v '^#' /etc/vfstab
++ grep pcfs
++ grep '[       ]/stubboot[      ]'
++ nawk '{print $1}'
+ bootdev=
+ '[' X = X ']'
+ is_pcfs_boot=no
+ check_zfs_boot
+ '[' -f /etc/lu/GRUB_slice ']'
++ df -n /
++ awk '{print $3}'
+ rootfstype=zfs
+ '[' zfs = zfs ']'
+ is_zfs_boot=yes
+ install_grub
+ STAGE1=/boot/grub/stage1
+ STAGE2=/boot/grub/stage2
+ '[' no = yes ']'
++ get_rootdev_list
++ '[' -f /etc/lu/GRUB_slice ']'
++ '[' yes = yes ']'
+++ df -k /
+++ tail +2
+++ cut -d/ -f1
++ rootpool=syspool
+++ LC_ALL=C
+++ zpool iostat -v syspool
+++ tail +5
+++ sed -n -e /--/q -e p
+++ egrep -v 'mirror|spare|replacing'
+++ awk '{print $1}'
++ rootdevlist='c0d0s0
c1d0s0'
++ for rootdev in '$rootdevlist'
+++ basename c0d0s0
++ echo /dev/rdsk/c0d0s0
++ for rootdev in '$rootdevlist'
+++ basename c1d0s0
++ echo /dev/rdsk/c1d0s0
+ grubdevlist='/dev/rdsk/c0d0s0
/dev/rdsk/c1d0s0'
+ zfsarg=
+ '[' yes = yes ']'
+ zfsarg=-Z
+ for rootdev in '$grubdevlist'
+ '[' X '!=' X ']'
+ echo 'Creating GRUB menu in /'
Creating GRUB menu in /
+ /sbin/bootadm update-menu -R / -Z -o /dev/rdsk/c0d0s0
Unsupported command. Please use 'apt-clone' command instead.
+ print 'Installing grub on /dev/rdsk/c0d0s0'
Warning: unknown mime-type for "Installing grub on /dev/rdsk/c0d0s0" -- using "application/*"
Error: no such file "Installing grub on /dev/rdsk/c0d0s0"
+ /sbin/installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c0d0s0
stage1 written to partition 0 sector 0 (abs 32130)
stage2 written to partition 0, 274 sectors starting at 50 (abs 32180)
+ for rootdev in '$grubdevlist'
+ '[' X '!=' X ']'
+ echo 'Creating GRUB menu in /'
Creating GRUB menu in /
+ /sbin/bootadm update-menu -R / -Z -o /dev/rdsk/c1d0s0
Unsupported command. Please use 'apt-clone' command instead.
+ print 'Installing grub on /dev/rdsk/c1d0s0'
Warning: unknown mime-type for "Installing grub on /dev/rdsk/c1d0s0" -- using "application/*"
Error: no such file "Installing grub on /dev/rdsk/c1d0s0"
+ /sbin/installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1d0s0
stage1 written to partition 0 sector 0 (abs 32130)
stage2 written to partition 0, 274 sectors starting at 50 (abs 32180)
+ exit 0