Alright, the root problem here, is that i don’t know the boot procedure of arm64 devices 
So, let me see if i figure all of this.
Correct, all files here are from your repo.
Ok, so starting from the beginning, so far these commands are correct, yes? They are done in NAND (openwrt). And no fip file flashing then:
echo 0 > /sys/block/mmcblk0boot0/force_ro
dd if=bpi-r4_emmc_bl2.img of=/dev/mmcblk0boot0
You mean compiling the full image, kernel included, in the R4? Ok, but before that, how do i flash and boot your image? Because so far, like you see above, i can only get the R4 to load boot stage.
Sure, can you please share the commands?
Oh BTW, i think this can be done without the usb drive. Like, in a remote machine: dd if=/some-image_here.gz | gunzip -c | ssh R4_ip dd of=/dev/whatever_partitions