On openwrt 15.XX i have seen if you installed additional Sofware via opkg and the /overlay path is nearby full you can’t save any settings via Luci Webinterface (blue Info box right upper corner) or the Router reboots hard automatic into failsave mode (lost all settings / factory reset)
Workaround:
- You can install a external usb stick on most routers and move the „/overlay“ folder to it
- You should always Download the „backup-settings.tgz“ from Software Menu to get the Router easy and fast online again on last working state.
- If the rootfs (root filesystem and overlay path) is nearby full, YOU CANT remove installed packages by „opkg“ packet manager, cause the ROM is readonly! For this reset the router and restore easy from „backup-settings.tgz“.
- If the external USB Drive loses connect to the Router (Power failure) and you use Samba as NAS Server the /overlay path can run full too!! and the Router can crash and reset too!! This shows openwrt should NEVER be used for secure routing jobs AND NAS Operations ! Cause it can you lock out!
Result: openwrt is a nice opensource router os which allows you to control and active monitor your internet connections with realtime graphs (WebUI+Console) and blocking rules. It should always be used behind a black boxed ISP router of your provider to get a private area!