Transfer a file using TFTP

Acronyms can be scary, lets face it.

Luck­ily, this one isn’t so bad.  TFTP stands for Triv­ial File Trans­fer Pro­to­col.  It’s very use­ful for trans­fer­ring small files from one node to another, and is kept sim­ple to avoid any issues.

What does that mean for us?  Some­times, when you’re flash­ing a router, a few things can happen.

1. You’ve not fol­lowed all the instruc­tions per­fectly, and you can’t get to your wire­less router’s GUI, with the stock or new firmware.
2. The router can­not be flashed by the GUI firmware upgrade at all, so you must use TFTP to trans­fer the firmware.
3. You think you’ve bricked your router.

Good news, if you can ping your router, you’re in good shape, and you might be able to sal­vage it.  Usu­ally the best thing to do for a failed flash upgrade, is to upload the orig­i­nal firmware for the router off of the router’s web­site (e.g. Linksys, Belkin, whatever).

If you’re using XP

For­tu­nately for XP users, a TFTP client comes pre-installed.

The syn­tax is:

tftp –i 192.168.1.1 put firmwarefile.bin

 

 

 

 

 

 

 

 

Replace 192.168.1.1 with the IP address of the router.  Dif­fer­ent brands have dif­fer­ent default IP addresses, but usu­ally the stan­dard is 192.168.1.1.

If you’re using Win­dows 7

For Win­dows 7, you have to install TFTP as a pro­gram fea­ture first before you can use it in the com­mand prompt.  To do this, go to start—and type in pro­grams and fea­tures, and click “turn win­dows fea­tures on and off.”  From the pop up box that comes up, check “TFTP client”.  You might want to check “Tel­net client”, too.  It might come in handy.

 

 

 

 

 

 

 

Fol­low the instruc­tions above for the XP TFTP client.

Tips

Tim­ing is every­thing for recov­er­ing from a bad flash.  The router must be in a mode to accept the firmware that you upload.  The best thing to do is to

1. Power cycle the wire­less router
2. Have a ping­ing ses­sion to your router active (ping 192.168.1.1 –t ) in one CMD window
3. As soon as it changes from “Des­ti­na­tion Host Unreach­able”, to “Reply from .…”, start the TFTP trans­fer.  (The TTL for the pings can be 100 or 128, rather than 64)

 

DD-WRT has a wiki page with some more detail here.