Contents

Wireless problems
Failsafe mode
1. How to get into failsafe mode
  1. All Models (RC5+)
  2. Older releases / model specific
    1. Linksys models
    2. Non-Linksys models
2. What should I do in failsafe mode?
Resetting to defaults
Recovering from bad firmware
Getting help

1. Wireless problems

If you have WPA encryption enabled, you need to install nas before wireless will connect.

ipkg install nas; reboot

2. Failsafe mode

If you've broken one of the startup scripts, firewalled yourself or corrupted the JFFS2 partition, you can get back in by using OpenWrt's failsafe mode. Full failsafe mode is only working when you have installed one of the SquashFS images.

2.1. How to get into failsafe mode

OpenWrt itself uses the reset button to enter into failsafe mode, and for no other purpose. In particular, it will not reset the NVRAM. The boot loader, however, may reset the NVRAM in response to the reset button. Therefore, it's important to know what's running when you hold down the reset button. One indicator is that OpenWrt will light the DMZ LED (on systems that have one) from the time it begins until the time the bootup scripts complete. If the DMZ LED has not yet lit up, you are still in the bootloader!

2.1.1. All Models (RC5+)

When OpenWrt boots, it will broadcast a UDP packet to port 4919 of network 192.168.1.x containing the message:

Press reset now, to enter Failsafe!

You can use the recvudp utility provided below, or a network monitor/sniffer to view the messages, for example nc -l -p 4919 -u. Remember, your PC must be set to have an address like 192.168.1.2 When the above message appears, press and hold the reset button for 2 seconds. You should now get the message:

Entering Failsafe!

2.1.2. Older releases / model specific

2.1.2.1. Linksys models

Plug in the router and wait for the DMZ LED to light up. Then immediately press and hold the reset button for 2 seconds. If done right the DMZ LED will quickly flash 3 times every second.

$/!\$ Holding the reset button before the DMZ LED turns on (i.e. when the bootloader is still running) can reset the NVRAM. Resetting the NVRAM will brick some models.

2.1.2.2. Non-Linksys models

Plug in the power, wait 2 secs, then press and hold the reset button for 10-15 seconds.

WGT634U - The failsafe button does not work on this router for Kamikazi builds. You will need to flash via a serial connection. Please refer to the hardware page for this model for specific failsafe routines.

2.2. What should I do in failsafe mode?

Once in failsafe mode, the router will ignore the configuration and use the ip address 192.168.1.1 and will boot directly into a telnet server, bypassing normal boot up. There will be no DHCP server, and the JFFS2 partition won't be mounted.

$/!\$ Tips:

Recover root, for example using Freifunk WEB interface you can change the password becouse not need authentication.
Your router will listen on the LAN port(s) only. You will not be able to connect via the WAN port in failsafe mode.
Failsafe has no DHCP, make sure you set a static IP address.
The act of switching between a normal boot and failsafe mode could change your MAC address! This will invalidate the ARP cache of the workstation you're using to access OpenWrt with. If you can't ping OpenWrt at 192.168.1.1 flush your ARP cache:

arp -d *

If you want to COMPLETELY ERASE the JFFS2 partition, removing all packages, you can run:

firstboot

to begin erasing, and then:

sync

to make sure that the Linux kernel actually commits this erasure to flash.

If you want to attempt to fix the JFFS2 partition, mount it with the following command:

/sbin/mount_root

3. Resetting to defaults

$/!\$ NOTE: Resetting NVRAM this way will actually cause more problems than it solves. For example, Asus WL-500g and the Motorola WR850G bootloader will not recreate default values and will not boot properly after being reset. If you do this on a Siemens SE505 V1, your router will not be accessible to you anymore! You will have to reflash it with the stock firmware on ip address 192.168.1.1 (NOT 192.168.2.1 as the installation procedure says!!)

To clean the NVRAM variables the safe way see the OpenWrt Faq.

If you're having trouble setting up some feature of your router (wireless, LAN ports, etc) and for some reason all of the documentation here just isn't working for you, it's sometimes best to start from scratch with a default configuration. Sometimes the various firmwares you try will add conflicting settings to NVRAM that will need to be flushed. Erasing NVRAM ensures there aren't any errant settings confusing your poor confused router. Run this command to restore your NVRAM to defaults:

mtd -r erase nvram

This will clear out the NVRAM partition and reboot (-r) the router, the bootloader will create a new NVRAM partition with default settings after the reboot. Remember to set boot_wait back on after you reboot your router -- trying to do it before rebooting will just write your old settings (cached in memory) back to the flash.

To reset NVRAM settings on a Siemens SE505 V1 simply press reset after you plug it in and release as soon as one of the leds starts flashing very fast.

4. Recovering from bad firmware

See OpenWrtDocs/Installing for generic installation instructions.

4.1. Software based method

Reflash the unit using the TFTP method.

4.2. Serial console

Important information about connecting a serial console can be found in OpenWrtDocs/Customizing/Hardware/Serial Console, Information about CFE can be found in OpenWrtDocs/Customizing/Firmware/CFE.

Set boot_wait=on in CFE and then TFTP the firmware image. To enter CFE hit CTRL-C right after power on.

CFE> nvram set boot_wait=on
*** command status = 0
CFE> nvram commit
*** command status = 0
CFE>

After this use the normal TFTP instructions found in OpenWrtDocs/Installing.

On Linksys models you can use another way too. Setup a local TFTP server on your PC and then execute the following commands inside CFE

CFE> ifconfig eth0 -addr=192.168.1.1 -mask=255.255.255.0
CFE> et up
CFE> flash -noheader 192.168.1.2:/openwrt-brcm-2.4-squashfs.trx flash1.trx

A simpler method is to have the CFE go into a voluntary boot_wait TFTP reception in this manner:

CFE> ifconfig eth0 -addr=192.168.1.1 -mask=255.255.255.0
CFE> et up
CFE> flash -noheader : flash1.trx

The CFE will enter TFTP receptive mode after that command.

4.3. JTAG adaptor method

Linksys models

refer to OpenWrtDocs/Customizing/Hardware/JTAG Cable howto create a JTAG cable
get HairyDairyMaids debrick utility or a more recent version from Downloads and instructions how to connect everything together
turn the router off, attach the jtag cable
turn it on, and issue one command
don't hurry, sometimes you'll need to wait a bit
BACKUP BEFORE MAKING ANY CHANGES

wrt54g -backup:cfe

will backup the CFE bootloader; you will need this later.

wrt54g -erase:nvram

will delete the nvram, if you just borked the nvram, you will be done here.

wrt54g -erase:kernel

if you've borken the kernel, you have to delete the kernel, in order to flash a new one

wrt54g -erase:cfe

if you managed to crap the cfe, you can delete it

wrt54g -flash:cfe

if you have the appropriate CFE.BIN image for your router in the same dir as the debrick utility, this will flash the router with the new cfe. Once you've flashed a CFE with boot_wait enabled, you can use tftp to upload a new kernel.

On Linux, don't forget to unload 'lp' module and load 'ppdev'.

5. Getting help

Still stuck? See how to get help and support for information on where to get further help.