Booting rock64 from USB SSD

Hi everyone,

I want to boot my rock64 from SSD (because all sd cards I could find are 
crap).

I followed those instructions to flash u-boot to SPI: 
https://github.com/ayufan-rock64/linux-build/blob/master/recipes/flash-spi.md

I was then able to boot FreeBSD from SSD (dd 
FreeBSD-13.0-RELEASE-arm64-aarch64-ROCK64.img to SSD, just like it would 
be to SD card), but ethernet wasn't working. Actually, it could receive 
packets but no outgoing packets were sent. Not even ARP packets - switch 
didn't detect any device on that port, but link was UP

I assumed it was something to do with u-boot, so I erased u-boot from 
flash, then DD FreeBSD-13.0-RELEASE-arm64-aarch64-ROCK64.img to SD card, 
and it worked without problems.

Do I understand correctly that this means that FreeBSD on rock64 uses 
custom u-boot? Can I somehow flash it to SPI?

Possible workaround that I can think of would be to put /boot on sd 
card, install u-boot to sd card, then put / on SSD.

Thanks in advance
-- 
Łukasz Moskała