what is the magic dd incantation to copy the system from the sd card to the emmc?

[calinb]

I did your test, wdt. I switched off my eMMC and the Armbian SD card will not boot from the PBP micro SD slot so, given that the boot order of the hard-coded SoC  ROM  is eMMC before micro SD, there is either no U-boot  code on the Armbian SD card or its code transfers control to the eMMC U-boot code.
Next I used dd to write PCM720's two U-boot files to the Armbian SD card and then it booted (with eMMC still disabled)! I've been using the PCM720 U-boot on eMMC for over a year now and it's been working well for me so I didn't want to mess with something newer and figured I'd try it on the Armbian SD card.
So Armbian boots from micro SD using PCM720 U-boot without eMMC memory enabled. What is different about Armbian that keeps it from booting when files or the image are copied to eMMC?

armbian uses boot.txt, run thru a simple compiler to make boot.scr
This is one of the things uboot looks for
While the kernel has to be configured to use nvme, 1st uboot has to find it (and be able to read it)

The text file is armbianEnv.txt, right? Yes--boot.cmd has a comment that says:

Code:

# Please edit /boot/armbianEnv.txt to set supported parameters

and also boot.scr:

Code:

# Please edit /boot/armbianEnv.txt to set supported parameters

But why is a compile even necessary when just moving the system to a new device that is obviously supported by the system when booted from SD? After I boot from SD, I can access both my eMMC and NVMe so it's obviously supported by the Armbian kernel. Is it a problem with initrd that requires it to be recompiled?
I don't understand this Armbian compiler requirement or the need for it. With other OSes on the PBP, it is sufficient to simply dd an image to a new memory device or copy the files over to a device that's already partitioned and formatted, as long a U-boot is valid.
Thanks!
-Cal