Recovery

First make sure have a known good firmware image.  Start by going to
    http://www.linksys.com/support/support.asp
Firmware images may also be downloaded from:
    ftp://ftp.linksys.com/pub/network

A static IP address must be configured on a computer which
is physically connected to one of the LAN ports on the back of the
WRT54G.  The default address of a new WRT54G is 192.168.1.1.
Assuming the WRT54G still has the IP 192.168.1.1, choose an
IP address which is the same except for the last octet.  For example,
192.168.1.2.  On a Unix / Linux system, the ethernet interface
may be configured with a command that looks like this:
    ifconfig eth0 192.168.1.2 netmask 255.255.255.0 up
The "eth0" part of the command may differ depending on exactly what
operating system is being run and what the name of the device is.

On Windows, a static IP address is configured via the Control Panel:

Control Panel -> Network Connections -> Local Area Connection ->
    Properties -> Internet Protocol (TCP/IP)

Then click on Properties.  Don't worry about the Default Gateway
setting or the DNS servers.  They need not be configured in order
for this procedure to work.

If the "boot_wait" parameter was set in NVRAM (detailed in the
installation instructions) then it is very easy.  Use any TFTP
(Trivial FTP) client.  When the WRT54G is powered on, one of the
lights on the front panel will blink rapidly.  While that light is
blinking, TFTP may be used to download a new firmware image.  The
TFTP session looks something like this:

$ tftp
tftp> connect 192.168.1.1
tftp> mode binary
tftp> put code.bin

It is recommend that you type in everything right up to the point
where you are ready to hit ENTER after typing "put code.bin".
Before hitting ENTER, plug in the power to the WRT54G.  As soon as
the light starts to blink, hit ENTER.

In Windows XP, the following command may work:
    tftp -i 192.168.1.1 put code.bin
Type that entire command in up to the point where you are ready to
hit ENTER.  Then apply power to the WRT54G.  As soon as the light
begins to blink, hit ENTER.

If you have no other hope, visit this page for detailed instructions
on how to recover a WRT54G:
    http://voidmain.is-a-geek.net/redhat/wrt54g_revival.html
We followed these instructions, and they really do work.

We recommend that you have the following tools available:

- A magnifying glass.  You are going to be counting very small pins
  on a very small chip on the WRT54G motherboard.

- A jeweler's screwdriver or some other very sharp, pointy, metal
  tool like a sharp pocket-knife blade.  Make sure it it is made
  of some material which conducts electricity.  This tool will be
  used to short two pins on the motherboard to reset the WRT54G.


SOME HELPFUL HINTS
------------------
Linksys uses a special variation of the TFTP protocol which requires
authentication via the router's password.  Normal TFTP does not
support authentication.  If the "Auto Upgrade" utility is downloaded
from Linksys, it contains a special TFTP client which supports
authentication.  For Unix / Linux, the source to a version of TFTP
which also supports authentication may be downloaded from:
    http://redsand.net/projects/linksys-tftp/linksys-tftp.php


When we followed "VoidMain's WRT54G Revival Tips", the following
situation was encountered:

We followed his instructions and got to the point where the firmware
image had been downloaded to the WRT54G via the tftp command.  But
the tftp download appeared to fail.  An error message came back
(something like "no space left on device".)  We immediately went
into a mild panic.

If this happens to you, DON'T PANIC.  In fact, don't do ANYTHING for
several minutes.  The WRT54G did, in fact, accept some / most of the
firmware image.  Just not all of it.  It will burn what it accepted
into the flash memory, then reboot.  Once the box has rebooted and
all the lights have stopped blinking, it will be in a state where
the configuration web pages won't work, but pretty much everything
else is working.

The special, authenticated tftp client (eether the linksys-tftp
utility downloaded from redsand.net above or the one supplied as
part of the "Auto Upgrade" utility) may now be used to download the
firmware image AGAIN.  This time the WRT54G will accept the entire
firmware image without error.