imx6q sd卡烧写android失败

你好，TQ工程师：
         我是按照提供教材烧写失败，如下uboot log，请帮忙分析下，谢谢！
U-Boot 2015.04 (Aug 19 2016 - 14:21:13)

CPU:   Freescale i.MX6Q rev1.5 at 792 MHz
CPU:   Temperature 34 C
Reset cause: POR
Board: MX6-SabreSD
I2C:   ready
DRAM:  2 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
*** Warning - bad CRC, using default environment

Display: CLAA-WVGA (800x480)
In:    serial
Out:   serial
Err:   serial
switch to partitions #0, OK
mmc0 is current device
Net:   FEC [PRIME]
Normal Boot
Hit any key to stop autoboot:  0
reading download.img
Error reading cluster
** Unable to read file download.img **
** Can't read partition table on 0:0 **
** Invalid partition 2 **
Kernel image @ 0x12000000 [ 0x000000 - 0x1ffb960 ]
ERROR: Did not find a cmdline Flattened Device Tree
Could not find a valid device tree


=================================================================
create_sdcard.sh


#!/bin/bash

# partition size in MB
BOOTLOAD_RESERVE=8
BOOT_ROM_SIZE=50
SYSTEM_ROM_SIZE=512
CACHE_SIZE=512
RECOVERY_ROM_SIZE=8
VENDER_SIZE=8
MISC_SIZE=8

boot_partition=2
images_partition=1

help() {

bn=`basename $0`
cat << EOF
usage $bn <option> device_node

options:
  -h        displays this help message
  -s        only get partition size
  -np         not partition.
  -f        flash android image.
EOF

}

# check the if root?
userid=`id -u`
if [ $userid -ne "0" ]; then
  echo "you're not root?"
  exit
fi


# parse command line
moreoptions=1
node="na"
cal_only=0
flash_images=0
not_partition=0
cp_images=0
not_format_fs=0
while [ "$moreoptions" = 1 -a $# -gt 0 ]; do
  case $1 in
      -h) help; exit ;;
      -s) cal_only=1 ;;
      -f) flash_images=1 ;;
      -c) cp_images=1 ;;
      -np) not_partition=1 ;;
      -nf) not_format_fs=1 ;;
      *)  moreoptions=0; node=$1 ;;
  esac
  [ "$moreoptions" = 0 ] && [ $# -gt 1 ] && help && exit
  [ "$moreoptions" = 1 ] && shift
done

if [ ! -e ${node} ]; then
  help
  exit
fi


# call sfdisk to create partition table
# get total card size
seprate=40
total_size=`sfdisk -s ${node}`
total_size=`expr ${total_size} / 1024`
image_rom_sizeb=`expr ${total_size} - ${BOOT_ROM_SIZE} - ${BOOTLOAD_RESERVE}`

# create partitions
if [ "${cal_only}" -eq "1" ]; then
cat << EOF
total :          ${total_size}MB
image_rom_sizeb: ${image_rom_sizeb}MB
EOF
exit
fi

function format_android
{
    echo "formating android images"
    umount ${node}${images_partition}
    umount ${node}${boot_partition}
    mkfs.vfat ${node}${images_partition}
    mkfs.vfat ${node}${boot_partition}
}
function copy_images
{
    echo "cp images..."
    mkdir mountpoint
#    dd if=/dev/zero of=${node}${boot_partition} bs=512 count=2
#    sync
    mount -t vfat ${node}${boot_partition} mountpoint
    rm -rf mountpoint/*
    sync
    cp imx6q-sabresd.dtb mountpoint/.
    cp download.img mountpoint/.
#    cp u-boot.bin mountpoint/.
#    cp boot.img mountpoint/.
#    cp system.img mountpoint/.
#    cp recovery.img mountpoint/.
    sync
    umount mountpoint
    rm -rf mountpoint
}

function flash_android
{
if [ "${flash_images}" -eq "1" ]; then
    echo "flashing android images..."   
    #dd if=/dev/zero of=${node} bs=512 seek=1536 count=16
    dd if=/dev/zero of=${node} bs=512 seek=1024 count=16
    dd if=u-boot_for_download.bin of=${node} bs=512 seek=2
#    dd if=imx6q-sabresd.dtb of=${node}${boot_partition} bs=512 seek=2
#    dd if=download.img of=${node}${boot_partition} bs=512 seek=2048
#    dd if=download.img of=${node}${boot_partition}
    sync
fi
}

if [ "${cp_images}" -eq "1" ]; then
    umount ${node}${images_partition}
    umount ${node}${boot_partition}
    copy_images
    exit
fi

if [[ "${not_partition}" -eq "1" && "${flash_images}" -eq "1" ]] ; then
    flash_android
    exit
fi


# destroy the partition table
dd if=/dev/zero of=${node} bs=512 count=2
sync
partprobe
fdisk ${node} << EOF
n
p
1

+${image_rom_sizeb}M
n
p
2


w
EOF


# adjust the partition reserve for bootloader.
# if you don't put the uboot on same device, you can remove the BOOTLOADER_ERSERVE
# to have 8M space.
# the minimal sylinder for some card is 4M, maybe some was 8M
# just 8M for some big eMMC 's sylinder

# format the SDCARD/DATA/CACHE partition
part=""
echo ${node} | grep mmcblk > /dev/null
if [ "$?" -eq "0" ]; then
  part="p"
fi

format_android
copy_images
flash_android


# For MFGTool Notes:
# MFGTool use mksdcard-android.tar store this script
# if you want change it.
# do following:
#   tar xf mksdcard-android.sh.tar
#   vi mksdcard-android.sh
#   [ edit want you want to change ]
#   rm mksdcard-android.sh.tar; tar cf mksdcard-android.sh.tar mksdcard-android.sh