Ethernet on ROCK64 SBC (RK2833)

[Wolfgang <mail%weirdrescue.pw@localhost>]

I'm having some problems with NetBSD on my ROCK64 SBC. After installing
a pre-built image by Jared McNeill (invisible.ca) I noticed that
Ethernet is not working properly - nslookup, ping and traceroute all
work well, both for the Internet and the local network, but i can't
download packages, use ssh or ftp: after entering a desired command
(say, "ftp ftp://address.com/file";) and pressing Return, nothing happens
anymore apart from the blinking cursor, that is, until I interrupt the
command manually.

I contacted Jared and he suggested that the problem might be caused by
this commit:
https://mail-index.netbsd.org/source-changes/2018/09/17/msg099237.html
and that reverting it apparently fixes the problem. However, my
knowledge of NetBSD is very limited and I don't know how to revert this
commit on my machine to make Ethernet work. Any help would be appreciated!