OpenWrt Failsafe Üzemmód
OpenWrt has a built-in failsafe mode which will attempt to bypass almost all configuration in favor of a few hard coded defaults, resulting in a router that boots up as
192.168.1.1/24 with only essential services running. From this state you can
telnet in and fix certain problems.
Reading Flash Layout, you should understand, that the OpenWrt failsafe can help you with any problems referring to the JFFS2 partition if you have a SquashFS image installed! In case you forgot your password or you firewall-ed yourself or you broke one of the startup scripts, you can get back in by using OpenWrt's failsafe mode.
Triggering via Hardware Button (Standard OpenWrt method)
Set your computer's IP to 192.168.1.2, subnet 255.255.255.0
Power cycle the router (turn off and turn on)
Immediately after the above step, rapidly click a button on the router for 60 seconds (it may be any button). Note: If your router has a ridiculously long boot time (such as DIR-300 A
), then you may do this for a longer time.
If done right, 192.168.1.1 will be pingable, and telnettable.
Telnet into 192.168.1.1 – there will be an immediate unauthenticated login to a root shell
Try out the commands below
Triggering via keyboard key combination in a serial console
Unplug the router's power cord.
Connect the router's LAN1 port directly to your PC.
Configure your PC with a static IP address between 192.168.1.2 and 192.168.1.254. E. g. 192.168.1.2 (gateway and DNS
is not required).
Plugin the power.
Connect via serial
Wait until the following messages is passing: Press the [f] key and hit [enter] to enter failsafe mode
Press "f" and the "enter" key
You should be able to telnet to the router at 192.168.1.1 now (no username and password)
In failsafe mode
You get a message like this "bla bla, you booted into failsafe mode"
NOTE: The root file system in failsafe mode is the only the SquashFS partition. The JFFS2 is not present. To mount JFFS2 in read-write mode run
and then repair your system:
In case you forgot your password, you need to set a new one. Type:
In case you forgot the routers IP address, get it with
uci get network.lan.ipaddr
In case you filled up the entire JFFS2 by installing too big/too many packages, clean the entire JFFS2 partition. All settings will be reset (OpenWrt equivalent of a factory reset)
mtd -r erase rootfs_data
If you are done with failsafe mode use
to reboot. (Normal
will not work, because
is not running.) Or power cycle the router.
the article process.boot
may help you better understand when
"kicks in" once activated