jz_write_bootsector.sh

#!/bin/bash -e
#
# Install binary program into boot sector of sdcard
#

confirm_or_exit() {
    read -r -p "$1 [y/N]: " response
    case "$response" in
        [yY][eE][sS]|[yY])
            return 0  # User confirmed
            ;;
        *)
            exit 1  # User did not confirm
            ;;
    esac
}

# this is the version of boot0 with EGON header attached
BINARY=nboot/boot0_sdcard_sun20iw1p1.bin

BSIZE=`stat -f%z $BINARY`
if [ $BSIZE -gt 65535 ]; then   # required to be < 64K
    echo "$BINARY ($BSIZE bytes) size too large!"
    exit 1
fi

echo "Available external disks:"
diskutil list external
echo "Review above list to find fullpath of disk you intend"
read -p "Enter disk dev path: " SDCARD
if [ ! -e $SDCARD ]; then
    echo "No such path $SDCARD. Cannot continue, exiting."
    exit 1
fi

diskutil info $SDCARD
confirm_or_exit "Are you sure you want to format $SDCARD and erase all data?"

diskutil unmountDisk $SDCARD
diskutil eraseDisk FAT32 MPIBOOT MBRFormat $SDCARD

echo "note: sudo-dd may require password"
diskutil unmountDisk $SDCARD
sudo dd if=$BINARY of=$SDCARD bs=8192 seek=16 # copy boot0 to bootsector

diskutil mountDisk $SDCARD  # mount disk, rename, populate with README & sample image
FAT_PARTITION="${SDCARD}s1"
diskutil rename $FAT_PARTITION MPIBOOT
cp README-sdcard.txt /Volumes/MPIBOOT/README.txt
if [ ! -f /Volumes/MPIBOOT/MANGO.BIN ]; then
    cp $CS107E/bin/blink-actled.bin /Volumes/MPIBOOT/MANGO.BIN
fi
echo "Here are contents of SD card"
ls -l /Volumes/MPIBOOT

diskutil unmountDisk $SDCARD  # unmount after write so able to eject