How all the OS images here were created

Prerequisite: install the debootstrap package on your Linux PC. It is available for most Distros, and as a standalone.

Note: all steps should be performed as root user

1. First step, on a x86 PC (I'm using Fedora. I'm telling you that to let you know you DON"T need Debian or Ubuntu.):
   

     mkdir rootfs

     debootstrap --foreign --arch armhf sid . http://ftp.debian.org/debian/  

2. Second step,
   

     cd rootfs

     tar cjvf rootfs.tar.bz2 .  

3. Third step (This can actually be shortened to two commands, and you can also do the above on the mmc itself, in which case you can just avoid the tar archive and this step.)
   

     mount /dev/mmcblk0p2 /mnt/misc

     cp rootfs.tar.bz2 /mnt/misc

     cd /mnt/misc

     tar xjvf rootfs.tar.bz2  

4. Next step, chroot on the armv7 armhf device (it does not need to be an A10 device, it can even be done using qemu) (This can also be done in rooted Android. Use the chroot script at the link above. Edit the script for the correct variables.)
   

     debian

     debootstrap --second-stage  

5. Final step
   Copy the kernel and modules and set up the correct password, networking, etc. for the rootfs.

As a final note I do most of this without an actual SD card using virtual disk images. We are going to be creating a script to automate the SD creation process. That is why I outlined this process here. Jeff's install script is a more complete template of how it is all done and can be automated. We would appreciate any comments or suggestions as we finish the full SD script. Our goal is to get an entire script that can be used on the device itself. It will use a partition to create an image which can then be burned to an SD card. An improvement over that script will be to do it faster on a PC using an x86 armhf virtual machine.

Others such as Rhombus have similar scripts. But they use Git, which in our opinion is not a good source for end-users. Git changes too frequently and bad commits have already caused major issues. Therefore we want our script to use stable binaries created from Git which will be updated frequently. That is the same way the major distros release their versions..