Linux host:
open terminal
cat [specified firmware].bin | nc -v -N -l -p 3333
remove -v if not working
open 2nd terminal and login in to OpenWrt box
ssh root@192.168.1.1
use 192.168.42.1 for Freifunk Berlin images
nc 192.168.42.102 3333 > /tmp/1.bin
192.168.42.102 3333 → host ip and port
sysupgrade -i /tmp/1.bin
-i interactive mode → keep config files?
be patient till box is up again