How To Reflash Factory Firmware on the NETGEAR WRN3500L Without A Serial Cable

When you upgrade to DD-WRT on your WNR3500L, you'll find that the new firmware requires a file that ends with the BIN extension, if you ever want to upgrade or change your firmware from that point.

So, if you decide, for example, to revert back to the original NETGEAR firmware - you can't because that firmware has a filename that ends in CHK.

As such, this makes it harder to change back. One way to do it is to use a serial console, but if you don't have one... here's a way to accomplish it in Windows without one.

Fortunately, included in the DD-WRT firmware is an erase utility that will wipe the firmware and allow you to upload a new one.

Here is how it's done.

You first have to Telnet into your router.

To do this simply open up a CMD window and type Telnet 192.168.1.1 (or the location of your router)

You will then need to type in the name and password for your router. If you have not changed it form the original setup, then they would be Name:admin and Password:password.

Once in, you will be shown a prompt that you can use to erase the old firmware.

Type in "erase linux" and it will run and show you its progress.

Once complete, it will again show you a command prompt.

Type in "reboot" and you should see "Connection to host lost"

You can then close this window.

Now we need to put the new firmware on.

Wait about 5 minutes for the router to reboot and then open up a new CMD window.

You will then use TFTP to put the new firmware on the router. This program comes with Windows XP. If you are using Vista, you need to install it.

1. Open the Control Panel and select the Programs entry.
2. From the Programs and Features section, select Turn Windows features on or off.

3. Scroll down the list and place a check in the box next to TFTP Client. Click OK.

4. Give Windows a moment or three to install the tftp client. When its done, exit out of the Control Panel.

Open up a CMD window and type in "tftp -i 192.168.1.1 PUT NameOfFirmware.CHK" as shown below.

Wait a few minutes and you should see "Transfer Successful"

At this point all you need to do is wait. The router will install the firmware and reboot automatically. This could take 5 to 10 minutes.

Once the router is finished booting you can go back into your browser and setup your desired configuration.

Tags: 

Vlad
Vlad's picture
With DD-wrt and Tomato (more

With DD-wrt and Tomato (more worst )firmware I did realize the router is very slow. The speed was really bad (WLAN transfer files). That was the reason to go back to the original firmware.

Vyri
Vyri's picture
@Cyring...........Same

@Cyring...........Same position as Vlad for me. Performance was absolutely terrible on WRT.

Cyring
Cyring's picture
Do you have any benchmarks ?

Do you have any benchmarks ? Because I did some with a RAM file system on both side, I mean two computers linked to the WNR and the gigabit rate was saturated
The DSL link is also at the top. Only Wifi could be better

Vlad
Vlad's picture
Hello. Not sure If I said

Hello. Not sure If I said before. I bought this N router for a better WLAN speed. Well at 4 m away from the router my WLAN speed for 15GB Folder transfer was 1.5 - 2 MB/sec with Tomato and DD-WRT. With Netgear I get 3MB. Tomato is looking nice and have some nice future there, but if no speed.
If I'm coming with my laptop near the router 1 m away, I get 9-10 MB /sec transfer speed with Netgear. and 6-7 MB with the others. My laptop has a N Wireless card inside and I follow the speed test in the Activity Monitor - Network. Hope this help. This was the reason I went back to the original firmware. Any way this router is not so good. 3MB/sec for a N router?!...

Cyring
Cyring's picture
You're right about Wifi rate,

You're right about Wifi rate, I'm crossing the same issue , however I prefer working on Desktop computers and for that usage this router is great & super fast , especially with a category 6 lan
I have the idea of adding a blacklist of Domains in dnsmasq like AD Blocking
It could also save WLAN bandwidth !

Vyri
Vyri's picture
 

 

Cyring said: Do you have any benchmarks ? Because I did some with a RAM file system on both side, I mean two computers linked to the WNR and the gigabit rate was saturated The DSL link is also at the top. Only Wifi could be better

I was lucky to get 1MB/s transferring files wirelessly at 20ft away from the router with WRT and had a very poor signal. I had no signal over 50% of my house. I spent 2 months trying make things better. As soon as I flashed back to stock Ifirmware  was seeing full signal and getting 4MB/s on file transfers. I also have full signal all over my house again. Never had any issues with WRT on LAN, only WLAN. No benchmarks needed to see stock is better for me.

 

Kleber J.
Kleber J.'s picture
The default U:P to telnet for

The default U:P to telnet for DD-WRT v24-sp2 mini telnet appears to be root:admin

At least for the version of the file from http://www.myopenrouter.com/download/25741/DD-WRT-for-SamKnows-WNR3500L-...

Also, after putting that mini build on,for IE8 web login times out. Firefox 3.6 worked though.

chetansha
chetansha's picture
I tried the above steps, but

I tried the above steps, but my router stays @ blinking green light.
Then i had to use tftp to put dd-wrt mini firmware to make my router usable again.

 

stiffy420
stiffy420's picture
What is the proper tftp

What is the proper tftp command on linux? when i use the command above, i get this reply:

usage: tftp host-name [port]

nikonja
nikonja's picture
I just uploaded Neatgear

I just uploaded Neatgear firmware normally from Tomato, as any other tomato firmware, so I don't understand this extra work you are suggesting.

jeff303
jeff303's picture
It appears I am stuck on DD

It appears I am stuck on DD-WRT, no matter what method of firmware update I try. For completeness sake, this is my router model: Netgear WNR3500v2/U/L .

For a while, I was using this DD-WRT firmware build, which I successfully installed from stock back in June 2013: dd-wrt.v24-21061_NEWD-2_K2.6_mini-WNR3500L.chk

However, I wasn't getting very good performance so I wanted to try Tomato, specifically the Shibby Tomato build that's linked from this router's page. But when attempting to use that file via the DD-WRT Firmware Upgrade Web GUI, nothing happens. The router just restarts, still with "DD-WRT v24-sp2 (03/25/13) mini - build 21061" still running.

So then I tried the procedure outlined here in an attempt to revert to factory firmware, to no avail. I tried using tftp to upload images of two different versions of the official firmware from the Netgear website (WNR3500Lv2-V1.0.0.14_37.0.50.chk and WNR3500Lv2-V1.2.0.18_40.0.67.chk), and the "official" Netgear firmware linked here (which is in the DDWRT_WNR3500Lv2_Support_Release_04-11-2012.tgz archive). None of these worked, the power light would just continue to flash green. It didn't matter how many times I sent the files by tftp, or how many times I performed the 30-30-30 reset in between attempts.

Eventually I realized that the DD-WRT version I started with would work without any problems (flashing green power light would go to yellow immediately after tftp transfer completed, and a few seconds later the router rebooted with DD-WRT working). This at least allowed me to "debrick" by getting the state back to where I started (via dd-wrt.v24-21061_NEWD-2_K2.6_mini-WNR3500L.chk). I also learned I could flash an updated version via tftp as well (build 22118 from: ftp://ftp.dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2013/07-24-2013-r...).

So, any suggestions on what else I can try to get either Tomato installed, or even the original stock firmware (from which I can presumably install Tomato)? I'm at my wit's end here. Thanks.

Update Dec 2013: I'm still stuck on DD-WRT. Warning: DD-WRT build 23138 (dd-wrt.v24-23138_NEWD-2_K2.6_mini-WNR3500L.chk) bricked my router when I attempted to flash it using tftp method as described above. I had downloaded it from the dd-wrt FTP site by browsing similar paths to the above and choosing a later date. It was broken to the point where I had to open the case (using this method in order to reset it back to build 14311. I found that no matter what I tried, flashing the Netgear factory firmware just didn't seem to work. The power light would stay blinking green after tftp completed (with ping of 100 TTL, which means waiting for firmware). I tried each of the following files: WNR3500Lv2-04061133.chk, WNR3500Lv2-V1.0.0.14_37.0.50.chk, and WNR3500Lv2-V1.2.0.18_40.0.67.chk. In each case, the firmware refused to take. Once I sent DD-WRT build 14311 again, the power light went to blinking yellow and reset immediately, rebooting within 3 minutes completely restored to DD-WRT.

jesseinsf
jesseinsf's picture
Um, I have the WNDR4500 and

Um, I have the WNDR4500 and when I use the "erase Linux" command it will complete its process and everything show like it did above. But when type the reboot command it reboots but nothing was erased. The DD-WRT firmware is still there. So I still get the failed connection when I do the TFTP command. What's going on here?

--UPDATE--
Just use the firware update in the DD-WRT GUI.... it worked for me. :-)

Deondone
Deondone's picture
Works!!

Works!!

Hallstrom
Hallstrom's picture
ZK

ZK

noblepayto
noblepayto's picture
Thank you for the good

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vpntoracc
vpntoracc's picture
Hello Every One,

Hello Every One,

1. I Have Netgear Nighthawk X6 (R8000) With DD-WRT Firmware.

2. Unfortunately I change overclocking setting from 1000MHz to
1400MHz now the router boots but I can't find Wifi Network or when I
plug the wire mannualy I can't ping the default gateway which is
192.168.1.1 and even I can't  access GUI.

3. Any Suggestion what should I do, Is it possible to fix the issue by flashing the nvram?

Please Help some one. Thanks..

vpntoracc
vpntoracc's picture
Hello Every One,

Hello Every One,

1. I Have Netgear Nighthawk X6 (R8000) With DD-WRT Firmware.

2. Unfortunately I change overclocking setting from 1000MHz to
1400MHz now the router boots but I can't find Wifi Network or when I
plug the wire mannualy I can't ping the default gateway which is
192.168.1.1 and even I can't  access GUI.

3. Any Suggestion what should I do, Is it possible to fix the issue by flashing the nvram?

Please Help some one. Thanks..

ronjohn
ronjohn's picture
Is there a way to reflash

Is there a way to reflash from tomato to stock?

ammy
ammy's picture
How to Setup your Netgear

How to Setup your Netgear Wifiext Range Extender?

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