BBB not taking saved image from microSD card

I am new to BBB and Angstrom and am having a problem getting my custom image of the eMMC on one of my BBBs to load onto my second board. Or back onto the board it was originally copied from. I am using the procedure from here “http://elinux.org/BeagleBone_Black_Extracting_eMMC_contents” and it copies the image to the SD card just fine. After I reverse the “if” and “of” settings and put in the newly created image name, I can get it to load onto the second BBB. I am running the latest image of Angstrom on a Rev B board. Below is the error I am getting when it attempts to run “autorun.sh”. If anyone can give me a some suggestions as to what I am doing wrong, I would greatly appreciate it. It looks like it is having a problem with the “dd” command.

My autorun.sh file:

#!/bin/sh
echo timer > /sys/class/leds/beaglebone:green:usr0/trigger
dd if=/mnt/BeagleBoneBlack-eMMC-image-24252.img of=/dev/mmcblk1 bs=10M
sync
echo default-on > /sys/class/leds/beaglebone:green:usr0/trigger

Error during load:

Running /dev/mmcblk0p1/autorun.sh…
sh: write error: Invalid argument

BusyBox v1.21.1 (2013-09-26 12:52:48 UTC) multi-call binary.

Usage: dd [if=FILE] [of=FILE] [ibs=N] [obs=N] [bs=N] [count=N] [skip=N]
[seek=N] [conv=notrunc|noerror|sync|fsync]

Copy a file with converting and formatting

if=FILE Read from FILE instead of stdin
of=FILE Write to FILE instead of stdout
bs=N Read and write N bytes at a time
ibs=N Read N bytes at a time
obs=N Write N bytes at a time
count=N Copy only N input blocks
skip=N Skip N input blocks
seek=N Skip N output blocks
conv=notrunc Don’t truncate output file
conv=noerror Continue after read errors
conv=sync Pad blocks with zeros
conv=fsync Physically write data out before finishing

Numbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),
MD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)