No, you can't update arm to armhf but you can create new image:
dd if=/dev/zero bs=1M count=2000 of=bodhi.ext4
mkfs.ext4 bodhi.ext4
mount it:
mount bodhi.ext4 /mnt
then download tarball:
mv bodhi.tar.xz /mnt/
cd /mnt
tar xJf bodhi*.tar.xz
chroot and create user
then move bodhi.ext4 to Mydocs and edit /home/user/.chroot with correct IMGFILE
after this install my deb in chroot image ("debian chroot" icon)
If you have problem try debwm in terminal. Remember to install kernel-cssu or newest kernel-power

Sorry for my bad English