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 192.168.11.1 -t -w 2
Notice the 192.168.11.1 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.
For whatever reason (Windows is stupid) you can't just add it through the arp command. Long story short you have to do a:
Find the "Number" associated with your ethernet interface, then type:
netsh interface ipv4 add neighbors ?? 192.168.11.1 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.
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
Some other folks have mentioned that they couldn't get the Linksys tFTP program to work... Pumpkin tFTP has yet to let me down.
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 192.168.11.1
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 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!