how to boot pinephone over USB with sunxi-fel?

[bobwidlefish]

Howdy friends,

I have PinePhone v1.2b hardware working fine with pmOS and Mobian, have serial console access working, and have "sunxi-fel version" showing success as well -- the phone seems to work fine, in general.
 
I'm trying to boot my PinePhone from USB using the FEL mode with a command like so:

Code:

sunxi-fel -v uboot u-boot-sunxi-with-spl.bin \
             write 0x42000000 uImage-postmarketos-allwinner \
             write 0x43000000 sun50i-a64-pinephone-1.2.dtb \
             write 0x43100000 boot.scr \
             write 0x43300000 initramfs-postmarketos-allwinner

Though I get an error regarding the u-boot image, so I tried to simplify, see as follows:

Code:

linux:~# sunxi-fel -v uboot u-boot-sunxi-with-spl.bin
Stack pointers: sp_irq=0x00012000, sp=0x00015E08
MMU is not enabled by BROM
=> Executing the SPL... done.
Invalid U-Boot image: bad size or signature
linux:~#

Any hints?  I'm using the u-boot-sunxi-with-spl.bin from here:
http://mirror.postmarketos.org/postmarke...228-r0.apk

-Bob