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Failsafe mode and sysupgrade: OpenWrt’s built-in ways back

A boot-time way back on 192.168.1.1; upgrades keep config.

In one sentence

Section titled “In one sentence”

Failsafe mode boots OpenWrt with a minimal, known configuration on 192.168.1.1, so you can fix a broken setup. sysupgrade replaces the firmware and keeps your configuration unless you tell it not to.

Failsafe mode

Section titled “Failsafe mode”
  • How to enter: during boot there is a 2–4 second window. Press almost any button on the device then, or press f and Enter on a serial console.
  • What you get: the router comes up on 192.168.1.1/24 with DHCP and wireless off and only essential services running. Give your computer a static address on that subnet, then connect over SSH.
  • What you can do: run mount_root to mount the overlay and repair files, or reset all settings with firstboot && reboot.
  • Failsafe needs a SquashFS image.

sysupgrade

Section titled “sysupgrade”
  • It keeps the configuration by default. -n flashes without keeping it.
  • sysupgrade -b <file> writes a .tar.gz backup of the files listed in sysupgrade.conf. -r <file> restores one, and -l lists what would be saved.

See it on your router

Section titled “See it on your router”

This command only reads:

Terminal window
sysupgrade -l | head

Watch out

Section titled “Watch out”
  • A factory reset erases every setting, so make a backup first.
  • Failsafe gives no DHCP. Without a static IP on your computer it looks as if the router is dead.
Section titled “Related guides”

Sources

Router.Homes

Independent OpenWrt notes. Every page states the firmware, device, package manager and way back.

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