Issues with REV A6

First of all, thank you for this post, it works great on my latest BBBs (REV C).  However, I cannot get it to work with my older BBBs (REV A6).  We have quite a few of the older versions laying around and would like to use those for some KIOSKs we are setting up in house.  Unfortunately, the script does not want to work on these boards.  The script is booting to the SD card but it does not appear to recognize (or mount) the eMMC.  I added `ls /dev > /mnt/dev.txt` to the bash script so I could see the device list, and there is only mmcblk0, there is not a mmcblk1.  I am powering the device with a 5V, 2A power supply and have disconnected all other cables (as suggested in other posts) and still no luck.  The device goes straight to a solid LED and writes the dev.txt and a 1KB img.gz file.  I have tried running it on multiple boards and am unsure what to try next.  Any thoughts as to why the eMMC is not being loaded/mounted?