[U-Boot] rk3288: firefly: flashing emmc from maskrom using USB

[Jack Mitchell]

I'm having issues flashing the emmc on my firefly board using USB. For
some reason it seems as though trying to write to the emmc flash sector
0x40 for uboot spl+proper from the Maskrom/Loader doesn't work. Can
anyone elaborate on what I'm doing wrong, or another way I could achieve
this?

The current state of the emmc is empty, so it boots into the maskrom on
reset.

I've tried with the Rockchip Loader binary as shown below:

$ tools/mkimage -n rk3288 -T rksd -d \
	spl/u-boot-spl-dtb.bin out && \
	cat u-boot-dtb.bin >> out

$ rkdeveloptool db RK3288Loader_uboot_V2.17.02.bin

$ rkdeveloptool wl 64 out

$ rkdeveloptool rd

This just loads back into the maskrom as if nothing was written to the emmc.

I've used the same method but writing to an sd card:

$ tools/mkimage -n rk3288 -T rksd -d \
	spl/u-boot-spl-dtb.bin out && \
	cat u-boot-dtb.bin >> out

$ dd if=out of=/dev/sdc seek=64

This works fine and boots into full uboot as I would expect, but from
the sd card rather than the emmc.

I have then flashed the emmc from the sd card running uboot, which then
enables me to boot uboot from the emmc.

I can also use rockusb from the sd card uboot to flash uboot to the emmc
using the following commands:

uboot> rockusb 0 mmc 0

$ rkdeveloptool wl 64 out

$ rkdeveloptool rd

This also works. However both working methods require me starting uboot
from an sd card in the first instance. How can I successfully flash the
emmc using just USB? Any input would be appreciated.

Regards,
Jack.