latest update:
BOTH the commercial openwrt GL inet BrumeW,
and the self flashed D1ink 842 (lastest snapshot) allow-ed ping, allow-ed FTP (port 2121), also normal CIFS (PC to PC, normal ports), but NOT modified samba (PC to android, above 3 ports).

While a TP1link C2 stock firmware allowed all.

So that should be openwrt’s setting I think.

thanks