VOLUME_NAME="Ubuntu KIKA"

(cd /tmp/custom/newiso && find . -type f -print0 | xargs -0 md5sum | grep -v "\./md5sum.txt" ) | sudo tee /tmp/custom/newiso/md5sum.txt

sudo genisoimage -r -cache-inodes -J -l \
    -b syslinux/isolinux.bin -c syslinux/boot.cat -no-emul-boot \
    -boot-load-size 4 -boot-info-table \
    -V "$VOLUME_NAME" \
    -o /tmp/custom-image.iso /tmp/custom/newiso/
sudo isohybrid /tmp/custom-image.iso

# optionaly update syslinux/isolinux.bin and syslinux/*.c32 with newer from syslinux, might make it more compatible with isohybrid below

sudo dd if=/tmp/custom-image.iso of=/dev/sdb bs=4M status=progress