BBB Dev help needed! I've got a potential RC version of Kamikaze 2.1 ready

BBB Dev help needed!

I’ve got a potential RC version of Kamikaze 2.1 ready on my uSD card, I can boot my BBB from it fine, it’s got all the bells and whistles we want in it. However when I tried extracting the image and distributing to a few willing beta-testers, their BBB wasn’t flashed as expected. I don’t yet have a sparse uSD card to try and push the image I created on it to test out the flashing procedure myself.

I’ve extracted the image by using dd if=/dev/mmcblk0p1 bs=16M of=Kamikaze-2.1.0-rc1.img (where mmcblk0p1 is the 2GB partition on my 8GB uSD card). Does anyone know if that is inherently wrong?