Hi SteeMan and thanks!
I have continued to fiddle with all of this. When I started, I was NOT on the true, stock, Android firmware for this box. I had installed alternate ROM. I finally considered this and went to the stock firmware before I started this process over again. I also more closely read your post (having glossed over the important part about looking for other dtb files (perhaps it would be good to BOLD that) and found there is one for my specific box - or so it seems based on the name. This way, things looked a bit more clean during the initial boot from burned SdCard, etc.
Having done this (but perhaps it was the same before - only I had not noticed it), once the copy script completes if I reboot the device without removing the SdCard, I find that the device does in fact boot directly into Armbian and starts the desktop. However, if I remove the SdCard and reboot, I get Android still. So it would appear that part of the boot code has made it into EMMC but also that the entire reset of the system did NOT.
When the system runs directly at power on the disk layout looks like this. I assume that mmcblk0 is the SdCard. Is this right?
Here is fdisk -x output:
Disk /dev/mmcblk0: 59.64 GiB, 64037584896 bytes, 125073408 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x80e20d40
Device Boot Start End Sectors Id Type Start-C/H/S End-C/H/S Attrs
/dev/mmcblk0p1 8192 1056767 1048576 ea Linux extended boot 0/130/3 65/199/6
/dev/mmcblk0p2 1056768 123797504 122740737 83 Linux 65/199/7 1023/254/63
Disk /dev/mmcblk1: 14.56 GiB, 15634268160 bytes, 30535680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mmcblk1boot0: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mmcblk1boot1: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/zram0: 961.96 MiB, 1008689152 bytes, 246262 sectors
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/zram1: 50 MiB, 52428800 bytes, 12800 sectors
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
After looking at the output of the install script and its source, I can see it has latched onto mmcblk1 as the emmc target. But in the code is it looking for mmcblk1p1 for the boot part and mmcblk1p2 for the root part. Neither exists it seems. There are mmcblkboot0 and 1 but I am not sure what might be done with them as they are smallish (4MB).
I am in really far over my head here...
Cheers