I got one of these on sale from NewEgg recently. The installation instructions in the git commit worked fine. This one had the older firmware, so the telnet instructions worked without issue.
One of the installation steps is to provide an http server. I found it easiest to do this using python. On the host machine I just ran
python3 -m http.server 8000
in the directory where the openwrt image was.
This device set the local subnet to 192.168.10.0/24 Then in the telnet session to copy the firmware, I used
curl -L -O http://192.168.10.125:8000/openwrt-ramips-mt7620-wavlink_wl-wn579x3-squashfs-sysupgrade.bin
Where 192.168.10.125 was the hosts' IP address assigned by the router.
Since I used the prebuilt snapshot image, there's no LuCI. Installing luci-ssl causes /overlay to go to 72% usage.
snapshot
root@OpenWrt:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 3328 3328 0 100% /rom
tmpfs 28564 80 28484 0% /tmp
/dev/mtdblock6 2320 136 2184 6% /overlay
overlayfs:/overlay 2320 136 2184 6% /
tmpfs 512 0 512 0% /dev
After luci-ssl install
root@OpenWrt:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 3328 3328 0 100% /rom
tmpfs 28564 1052 27512 4% /tmp
/dev/mtdblock6 2320 1680 640 72% /overlay
overlayfs:/overlay 2320 1680 640 72% /
tmpfs 512 0 512 0% /dev
I'll probably be trying to build my own image, but I'm concerned about using too much space.