If you use a TP Link Router like 3600, 4300 or a other brand with ATH9K Chipset you should upgrade to OPENWRT 18.06 with Kernel 4.9 Tested: OpenWrt 18.06.0 r7188-b0b5c64c22 / LuCI openwrt-18.06 branch (git-18.210.69179-6df9a57) – Atheros AR9344 rev 2 cause: more stable less load no ath9k Wifi Lookup on high transfers Same seen on other TP Link Routers like 841 Series, remark last Version 13 not supported Hope that the Freifunk Software will be updated fast! More Information go: https://openwrt.org/