I just purchased a Netgear router,  model WNDR3800-1CHNAS.

Trying to install factory OpenWRT, but cannot.  The firmware loader in the router's GUI recognizes OpenWRT but just responds with "Firmware upgrade failed. Please check your file."

I even tried downgrading Netgear's own firmware from V1.0.0.51CH to V1.0.0.16, but even that got the same error.

TFTP from factory reset doesn't work either, I can put the .img file but it just keeps flashing the green LED and won't do anything until I power-cycle (then just loads V1.0.0.51CH again).

Has anyone here been able to get past the stock firmware for this particular model of WNDR3800? What else can I do?

It is probably some China-specific model, right?

Checking from Netgear's site it looks like it has a separate firmware ID:
http://kb.netgear.com/app/answers/detai … -%28gpl%29

Most likely it has a different firmware ID and to successfully flash another firmware to it, the other firmware should first be modfied to contain the required ID string. Then the OEM TFTPmode or upgrade will accept the new firmware as genuine/compatible.

3700v1 used to have similar North America version and Openwrt contains mod for that ( the -NA version). Probably someone should analyse that CH version original firmware and define the needed patch.

EDIT:
The difference gets embedded to the firmware file's header info. See example regarding WNDR3700v1. Region code NA has been set in the firmware.
Normal WNDR3700v1 factory.img:

00000000  64 65 76 69 63 65 3a 57 4e 44 52 33 37 30 30 0a 76  device:WNDR3700 v 
00000011  65 72 73 69 6f 6e 3a 56 4f 70 65 6e 57 72 74 2e 72  ersion:VOpenWrt.r 
00000022  33 39 37 38 39 0a 72 65 67 69 6f 6e 3a 0a 00 00 00  39789 region:     
00000033  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000044  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000055  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000066  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000077  00 00 00 00 00 00 00 00 00 33 37 30 30 93 ec 7b 06           3700“ì{ 

North America version:

00000000  64 65 76 69 63 65 3a 57 4e 44 52 33 37 30 30 0a 76  device:WNDR3700 v 
00000011  65 72 73 69 6f 6e 3a 56 4f 70 65 6e 57 72 74 2e 72  ersion:VOpenWrt.r 
00000022  33 39 37 38 39 0a 72 65 67 69 6f 6e 3a 4e 41 0a 00  39789 region:NA   
00000033  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000044  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000055  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000066  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00                    
00000077  00 00 00 00 00 00 00 00 00 33 37 30 30 93 ec 7b 06           3700“ì{ 

If you want to experiment, check with a hew editor the first bytes of the original China version. Is there a CH region code? If yes, then you might try hex editing the Openwrt firmware file to contain the same CH: "43 48 0a" (?) instead of the default "0a 00 00".

(Last edited by hnyman on 8 Mar 2014, 09:41)

I just received two of this "WNDR3800CH" and I'm having the same problem. Were you able to modify firmware file's header and successfully install openwrt?

I made a post in the dev forum, see
https://forum.openwrt.org/viewtopic.php?id=51025
or the
github diff

An image gets generated but I dont know if it works
feel free to test, give feedback here or on the mailing list so it can be added

I looked at the GPL package when creating the patch and compared it to default WNDR3800 so it should work but I cannot test it

(Last edited by zloop on 12 Jun 2014, 07:56)

Thanks to zloop, I was able to successfuly compile and install openwrt on my Netgear wndr3800-1chnas (wndr3800ch).  Worked like a charm!

Big ups to Zloop for the specific header strings.

(Last edited by ipood on 6 Jul 2014, 20:47)

Would you mind uploading the compiled image for WNDR3800-1CHNAS? I'd like to test it. I tried compiling it but I'm getting error messages before the image is generated.

@aanglere - I've uploaded an image you can try: http://bayfiles.net/file/1iPCj/P7eN3N/o … actory.img

Hey it worked for my first flash.
Then I did sysupgrade through web interface for the firmware I wanted which wasn't patched for wndr3800CN and it went through fine.

Thanks a lot!

(Last edited by robnitro on 4 Aug 2014, 23:13)

So I'm another one who landed a WNDR3800-1CHNAS. I wanted to test out the OpenWireless firmware ( https://openwireless.org/content/open-w … stallation ) , and used their link to the refurbished WNDR3800 ( http://www.newegg.com/Product/Product.a … 6833122523 )

Anyway, ran into the same issues described in the posts above.

That worked for me, but now how do I access the web interface with that? ( http://routerlogin.net gives me nothing now. )

So what firmware are you running now on it?

Routerlogin.net is a Netgear feature. You'll want to go to http://openwrt.lan or http://192.168.1.1 for stock OpenWrt. Not sure about OpenWireless.org FW. CeroWrt is also a bit different with their naming and numbering scheme.

Nah, those addresses aren't working either. Router works enough to get online on bharder's image, but I can't figure out how to configure it. I have Putty and read over http://wiki.openwrt.org/doc/howto/firstlogin

And if I had to I know how to do a firmware recovery https://www.youtube.com/watch?v=0K8sVuCrPt4 (but if it did get to that point, I'm not sure what other firmware to throw on it)

I dunno, have to play around with it more. If anyone thinks of anything, let me know. Thanks!

Does this build include Luci? Try installing that. http://wiki.openwrt.org/doc/howto/luci.essentials

support for WNDR3800CH has been added to trunk today.
https://dev.openwrt.org/changeset/42023

The next buildbot snapshot should included the "official" version for WNDR3800CH.

(Last edited by hnyman on 7 Aug 2014, 08:23)

Got it: http://downloads.openwrt.org/snapshots/ … actory.img

Works!

(Case anyone else is new to this stuff, it was under http://downloads.openwrt.org/snapshots/trunk/ar71xx/ )

Alright, that helped a ton! Thanks, man.

The wiki appears to be down. How do I install Luci?

Similar problem here.

I have Netgear WNDR3800CH running 1.0.0.61CH

It seems like the patch made it to the main repository but I'm having trouble... When using GUI of the router I'm getting: "Firmware upgrade failed. Please check your file."

I did some searching and found:

So I downloaded the old drivers from Netgear - and tried again - "Firmware upgrade failed. Please check your file."

Just wondering if there is "an easy" way to install OpenWRT or do I have to do bootloader shananigans?

(Last edited by stefek99 on 1 Oct 2016, 12:03)