flash_uboot() {
  if [[ ! -e /dev/mtd0 ]]; then
    echo '>> Error: /dev/mtd0 does not exist.'
    return
  fi
  # set up config for fw_printenv/setenv
  echo '/dev/mtd0 0xc0000 0x20000 0x20000' > /etc/fw_env.config
  # save MAC address
  mac=$(fw_printenv | grep ethaddr | cut -d= -f2)
  if [[ $mac == '' ]]; then
    echo '>> Error: Could not find MAC address from current U-Boot.'
    return
  fi
  # flash U-Boot
  flash_erase /dev/mtd0 0 4
  flash_erase /dev/mtd0 0xc0000 1
  nandwrite /dev/mtd0 /boot/uboot-goflexnet.kwb
  nandwrite -s 0xc0000 /dev/mtd0 /boot/uboot-goflexnet.env
  # set MAC address
  fw_setenv ethaddr ${mac}
}

ask_uboot() {
  echo "A new U-Boot version needs to be flashed to NAND."
  echo "Do you want to do this now? [y|N]"
  read -r shouldwe
  if [[ $shouldwe =~ ^([yY][eE][sS]|[yY])$ ]]; then
    flash_uboot
  else
    echo "You can do this later by re-installing uboot-goflexnet."
  fi
}

## arg 1:  the new package version
post_install() {
  ask_uboot
}

## arg 1:  the new package version
## arg 2:  the old package version
post_upgrade() {
  ask_uboot
}