Unbrick Buffalo WZR-HP-G300NH Router with Solid Diag and Endless Reboot

Sunday, January 02nd, 2011
Last Updated:
Saturday, December 21st, 2013

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I came home one night to find that my internet wasn't working... So, I go check the cable modem and notice it looks fine, then look at the router, a WZR-HP-G300NH to see a solid green power light and a solid red diag light. After about 45 seconds, all the lights would come on, then shut off and repeat the process, rebooting itself every 45 seconds or so.

Searching around trying to find the "right" information on debricking a Buffalo WZR-HP-G300NH router, sent me to countless forums and all sorts of "try-this-try-that" scenarios. I am not a fan of forums because everyone has the same problem, but no one ever has a solid fix... Well, after pulling my hair out, I finally figured out how to re-flash my endless reboot router back to a good ol' DD-WRT firmware, using Pumpkin TFTP. I realize someone else has probably already blogged on this, but I didn't find their page that was specific to the solid diag & endless reboot, so I'm trying to get some SEO going for that specific problem.

First off, if you try to ping the router in this state, you WILL NOT see it... I have a feeling ICMP is turned off because I couldn't even get a reply after setting a different timeout period on ping. ping -t -w 2

Notice the This is the IP of the router when it's in the endless reboot cycle (or) the double blinking diag.

Secondly, I did all of this in Windows 7. Most of the forums and guides, show how to use Linux. For those of us who don't use Linux on a regular basis, I can tell you this DOES work on windows. (Dunno about XP?)

For the most part, I'm going to use what other's have pieced together already, with a few of my own tid-bits to help bring things along. Keep in mind, I blog stuff so I can go back and have a solid guide on how to fix something... Take this info "AS-IS".

I recommend that you take a look at the instructions all the way through, before proceeding with things.

  1. Go out to: http://g300nh.blogspot.com/2010/06/firmware-flash-and-brick-recovery.html and take a look on how you need to setup your computer to transfer the file. The only part you really need to know, is getting the ARP setup so points to the MAC address of your router. Once you have this part, move to step 2

    For whatever reason (Windows is stupid) you can't just add it through the arp command. Long story short you have to do a:

    route print

    Find the "Number" associated with your ethernet interface, then type:

    netsh interface ipv4 add neighbors ?? xx-xx-xx-xx-xx-xx

    Where ?? is your interface number and xx-xx... is the routers mac address.

    Note About The MAC: Most routers have a sticker on it that says mac: xx-xx-xx-xx-xx-xx. On the WZR-HP-G300NH, the MAC address is the same thing as what the "SSID" is... Weird and nonconformant, but whatever. Look to the SSID for the mac address.

  2. Next, we are going to download the firmware that will allow you to get things going. This is the stock firmware, provided by Buffalo and there are two version to note:
    1) the proprietary Buffalo version - Official
    2) the Buffalo DD-WRT version

    In order to unbrick it, you will need the Official version. I am yet to get the DD-WRT Buffalo version to work. If you do want to move over to DD-WRT after it's unlocked, I recommend getting both the Official and DD-WRT versions. Just make sure you flash the "Official" version first. Then you can upgrade to DD-WRT using the web interface and finally update to a non-buffalo DD-WRT firmware.

    To get the downloads, go to the official Buffalo Support site:

    Select the router from the drop down and you will find the two firmware versions listed. As of this writing, (2011/01/02) the two versions available are:
    1.76 - Official
    V24-SP2 build 14998 - DD-WRT Professional

  3. Now that you have the IP set on your computer to something like, the ARP setup for the router MAC and the necessary files downloaded, go out and download the tftp program I recommend which is Pumpkin TFTP and can be downloaded here.

    Some other folks have mentioned that they couldn't get the Linksys tFTP program to work... Pumpkin tFTP has yet to let me down.

  4. Launch Pumpkin TFTP program, point to the firmware you wish to push, whether it's the official or DD-WRT Professional and begin the transfer. At this point, it's assumed that your router is unplugged. Plug-in your router and the transfer should begin around 15 seconds of it being turned on. Watch for the "send" process and once it's completed, the router diag light will begin to blink for a couple of minutes. DO NOT turn it off during this process. If it takes longer than say... 15 min, you might unplug it and try it again. Some have reported that it takes every bit of 15 minutes before it reboots. I think it only look mine around 10 though. If you want to be safe, then wait 20 :)

    If for some reason you get a double blinking diag light at any point, unplug the router and try to re-send the firmware through tFTP. The diag light should stay solid for about 20 seconds before it goes to the double diag blink.

If the router doesn't reboot on it's own after the flash is complete, (Wireless light blinking) and it's back to a solid diag light, go ahead and un-plug it and plug it back in. If it works successfully, you should now be able to access the web interface at

If you decided to put the Buffalo DD-WRT professional version on so you can upgrade to the latest DD-WRT version, simply download the webupgrade version of DD-WRT for the router and flash it through the web interface.


  • If you successfully flash the firmware and you can't access the web interface or ping the router ip (, chances are there's something screwy with the arp table. Try issuing the arp -d command to clear your arp cache, then re-add the router mac using the netsh command listed above.

If I forgot something, or you want me to add / change something, feel free to let me know and if this works for you, let others know in the comments!

Post Comment


manual arp entries get lost on winxp pro!
host os: windows xp pro sp3
hardware version: b0 b0
situation: endless reboot after web flashing to updet dd-wrt
* desperate need to daily internet doze :)
* don't have access to windows 7 nor linux
* don't have switch to put between computer and router
* manual arp entries get lost every some time (defenitely fewer than 60sec, dunno what the cause is, but probably something related with network connection sensing)
* router "window" to receive new firmware is really short
* seems that u-boot accepts only *.enc files or files with specific information in their header (dd-wrt firmware files were transferred, but endless reboot continues): used buffalo firmware wzrhpg300nh-177.enc (version 1.77 dated 2011.02.28)

* connected computer to router's lan port nearest to the wan port
* to change ip address without need to reboot: use netsetman ( http://www.netsetman.com it is freeware and one option to install is just unpack)
* wrote little bat file that assigns an arp entry and starts tftp transfer
* fired the bat file around 12sec after powering the router (lower values (6sec, 8sec or 10sec) doesn't worked), counted seconds "manually"
* after successful tftp transfer diag light got from solid to blinking, waited after router next reboot (not very long, some 4-5 minutes or so) and no more diag light and router web interface was accessible wia (username: root; password: {nothing, just hit enter})

bat file:
arp -s 02-AA-BB-CC-DD-1A
arp -a
tftp -i put wzrhpg300nh-177.enc

This worked for me - after many gyrations around and around.

Situation: Bad flash left me with a solid power light and DIAG light. No response to Ping, or any other probes of the device.


Using Windows XP Pro, and a direct wired connected between the laptop and the Buffalo. Used LAN port 1 (furthest from the WAN port) - so I don't know if it matters which port is used,

Changed the network card to 100Mbps and half-duplex (not sure if the HD was required),,,

Downloaded a *.enc file from the Buffalo website,

Created the *.bat file shown above. Using the 02-AA-BB-CC-DD-1A MAC address was required (not the true MAC address of the device),

Get everything ready on the laptop. Power on the Buffalo. Wait 12 seconds (until the laptop says the ethernet card is connected), then start the bat file,

Smile - as the DIAG light starts to flash and otherwise show life.

Be patient, and wait for the router to load the new firmware, and start up.

straight to the point!! thank you!!!!

How do i figure out what the buffalo's MAC adress is?

The MAC address is usually either on the side of the case, or on the bottom. It will be a random string of letters and numbers with dashes or a colon between them. There are 12 total characters and the letters will never go past the letter F. (A-F and 0-9)

For example, you're looking for something with a pattern of:

xx-xx-xx-xx-xx-xx or xx:xx:xx:xx:xx:xx

A Real World example will look like:

9E-54-95-2D-50-62 or 91:BF:7A:16:CA:17

In some rare cases, vendors will print the MAC address without any separator like so:
0F 35 95 E9 B5 DA

Hope that helps!

Yeah, my router bricked on me tonight... again...

Needing the MAC, I went looking for the sticker to find it. Only, the sticker doesn't say "mac: xx-xx-xx-xx-xx-xx" like 99% of the other routers on the market do.

Instead, the mac address is the same thing as the SSID on the sticker.

I've updated the guide to point this out and sorry it took so long to get a better answer for you.

Tested with WZR-HP-G300NH v1 and works fine.
Using Router as I typing comment.

thanks for the guide, i was searching around and found a few pages on how to debrick the router, the main thing is to set the arp right, i tried linksys tftp, it failed on me at least 10 times. after finding your post, i changed to use the pumpkin tftp, and it worked flawlessly the 1st time i use it, it shows the transfer status and got the router back to normal within 20 mins. thank u again

This method worked for me but had to turn off Windows firewall first!

In step 1 you state "The only part you really need to know, is getting the ARP setup so points to the MAC address of your computer."

I thought it was supposed to point to your router.

Please clarify.

Thanks for your efforts, you're right about all the different and conflicting info re. unbricking a wzr-hp-g300nh.

Yeah, after looking at it, you are right. Step 1 should have said "MAC Address of the Router". I have updated the content to reflect the proper device. (Doesn't make sense to point the IP to the computer's MAC huh? :p)


You saved my butt with this one...power went out in the middle of a flash...it was bricked! This article/tutorial saved my router and i appreciate it...THANKS

I had to delete neighbours before it would work, but now it's great. thanks for the blog post!! :D

This seemed to work for me, no more rebooting after red diag light. Now I have wifi symbol going on and off intermittently, which is apparently normal.

Unfortunately I uploaded the "V24-SP2 build 14998 - DD-WRT Professional" image as suggested above, and now I cant find the IP address of the router. and don't seem to work, so I haven't been able to connect to it.

The wifi seems to be working - it gives me an SSID to connect to that is very similar to the SSID printed on the back of the router, but I don't know what password to use..

Any ideas appreciated! :-)

You have to wait a really really really long time after the TFTP transfer completes, during which the DIAG light blinks steadily, until the router reboots. If you turn it off before it reboots its self, it just bricks the router again.

After the TFTP, wait a REALLY long time.

Great guide - thanks.
Confirmed working for WZR-G301-NH.
Just wanted to reiterate the above post - once you have flashed the router the red diag light will flash red for up to 15 minutes before rebooting and coming back to life.

I know this site is rather old & probably no longer updated, but I just got (2) of these routers (both bricked) and now they both work !!! Thank you so very much !

Thanks Ben! Glad you got it going :-) The site's pretty old (been around since 2007) but it still gets some tender love from time-to-time. This page is pretty old though and while I still have my Buffalo routers, I've moved on to hardware firewalls and Google Wifi for my setup which is a breath of fresh from the days of trying to manage DD-WRT. I'm not a big fan of my hardware firewall, but I absolutely love the Google Wifi. It just works... All the time...

Good luck to ya and hope you get some great service out of those routers!