[...]
 function _create_sdcard {
         # putting it all onto SD card
         DEST_DEVICE="$1"
         test -b "$DEST_DEVICE" || die "Must give block device with SD Card as first parameter"

         _umount mnt/img_root/{proc,sys,run,dev/pts}

         echo "Preparing SD card in $DEST_DEVICE"
         umount -f ${DEST_DEVICE}* &>/dev/null || :
         dd if=/dev/zero of=$DEST_DEVICE bs=1M count=100 status=none || die "Could not wipe SD card in $DEST_DEVICE"
         parted -a minimal -s $DEST_DEVICE mklabel msdos mkpart primary fat32 0mb 64mb     mkpart primary ext2 64mb 100% set 1 boot on || die "Could not parted $DEST_DEVICE"
         if [ -e ${DEST_DEVICE}p1 ] ; then sd_boot_dev=${DEST_DEVICE}p1 ; elif [ -e ${DEST_DEVICE}1 ] ; then sd_boot_dev=${DEST_DEVICE}1 ; else die "Could not find sd-card partition 1" ; fi
         if [ -e ${DEST_DEVICE}p2 ] ; then sd_root_dev=${DEST_DEVICE}p2 ; elif [ -e ${DEST_DEVICE}2 ] ; then sd_root_dev=${DEST_DEVICE}2 ; else die "Could not find sd-card partition 2" ; fi
         mkdir -p mnt/sd_boot mnt/sd_root
         mkfs.vfat >/dev/null -n RASPBIAN_BOOT -F 32 $sd_boot_dev -m - <<<"This is the boot partition of a Raspbian image intended for a Raspberry Pi" || die "Could not create boot partition"
         mkfs.ext4 -q -L raspbian_root -E discard $sd_root_dev || die "Could not create root partition"
         tune2fs >/dev/null $sd_root_dev -o journal_data,discard || die "Could not tune2fs $sd_root_dev"
         mount -o data=writeback,nobarrier -t ext4 $sd_root_dev mnt/sd_root || die "Could not mount $sd_boot_dev mnt/sd_boot"
         mkdir -p mnt/sd_root/boot || die "Could not mkdir boot"
         mount -t vfat $sd_boot_dev mnt/sd_root/boot || die "Could not mount $sd_boot_dev mnt/sd_root/boot"

         echo "Copying files to SD card."
         cp -a mnt/img_root/* mnt/sd_root/ || die "Could not copy root fs"

         echo "SD Card Details:"
         _op parted -s $DEST_DEVICE print
         df -h mnt/sd_root/boot mnt/sd_root | sed -e "s#$(pwd)/##"

         sed -i -e 's/#//' mnt/sd_root/etc/ld.so.preload || die "Could not enable ld.so.preload"
         echo
         echo "SD Card Creation finished, please wait for script to complete."
 }
 [...]