Some speculative changes to support cubieboard2 image builds

src/freedombone-image-customise

 chroot "$rootdir" apt-get install -y avahi-daemon avahi-utils avahi-discover avahi-autoipd
 chroot "$rootdir" apt-get install -y iptables dnsutils net-tools network-manager
 chroot "$rootdir" apt-get install -y libnss-mdns libnss-myhostname libnss-gw-name
+chroot "$rootdir" apt-get install -y u-boot-sunxi
 
 chroot "$rootdir" /bin/bash -x <<EOF
 git clone https://github.com/bashrc/freedombone /root/freedombone

src/freedombone-image-hardware-setup

     initRd=initrd.img-$version
     vmlinuz=vmlinuz-$version
 
-    # boot.cmd for CubieTruck
+    # boot.cmd for Cubieboard2
+    # https://downloads.openwrt.org/chaos_calmer/15.05/sunxi/generic/uboot-sunxi-Cubieboard2/openwrt-sunxi-Cubieboard2-uEnv.txt
     cat >> /boot/boot.cmd <<EOF
 setenv mmcdev 0
 setenv mmcpart 1
 setenv kernel_file $vmlinuz
 setenv initrd_file $initRd
 
-setenv loadaddr 0x46000000
-setenv initrd_addr 0x48000000
-setenv fdtaddr 0x47000000
+setenv loadaddr 0x41000000
+setenv initrd_addr 0x43000000
+setenv fdtaddr 0x42000000
 
 setenv initrd_high 0xffffffff
 setenv fdt_high 0xffffffff
 run loadfiles; run mmcargs; bootz \${loadaddr} \${initrd_addr}:\${initrd_size} \${fdtaddr}
 EOF
 
-    # boot.scr for CubieTruck
+    # boot.scr for Cubieboard2
     mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr
 
-    # DTBs for CubieTruck
+    # DTBs for Cubieboard2
     mkdir -p /boot/dtbs
     cp /usr/lib/$kernelVersion/* /boot/dtbs
 

src/freedombone-image-make

  --roottype btrfs \
 "
     ;;
+    cubieboard2 | cubietruck | a20-olinuxino-lime2 | a20-olinuxino-micro)
+       extra_pkgs="$a20_pkgs"
+       extra_opts="\
+ --variant minbase \
+ --bootoffset=1mib \
+ --bootsize 128M \
+ --boottype vfat \
+ --no-kernel \
+ --no-extlinux \
+ --foreign /usr/bin/qemu-arm-static \
+ --roottype btrfs \
+"
+       ;;
     virtualbox)
     extra_opts="\
  --grub \