[naasking]

I have a netgear WNDR3700v3 that's running DD-WRT v3.0-r29440 mega that I've been using as a switch. I want to revert it to stock or upgrade the DD-WRT running on it. I just can't seem to get it to install any image, either stock, DD-WRT or OpenWRT, it always just boots back to the existing DD-WRT.

I've tried:

* GUI firmware installation: the connection resets and the browser shows a connection reset error after 3-5 seconds and the router reboots. This happens even if I have a switch in between my computer and the router. I've tried flashing both the stock firmware and DD-WRT and OpenWRT, same result. I've also tried Chome, Firefox and Edge, they all reset in similar ways.

* TFTP installation: I've tried both Windows tftp client and tfpd64, and I've tried holding the reset button under the router during boot [2,3,4] and not [1], I've tried waiting for TTL=100 before trying the tftp upload and running it before and after that, dozens of times, nothing seems to work and the tftp attempt just times out. Holding the reset button while it's powering on leaves the ethernet ports unresponsive to pings and the power LED remains amber with no other LEDs activating until I release the reset button (I've held it for 2+ mins with no change and no ping response), so failsafe/recovery mode doesn't appear to work [5]. The inability to engage recovery mode has the same symptoms as user o0camilo0o posted about here, but nobody replied to that message so I don't know if there's a resolution. When I release the button the other LEDs come on soon after (like wifi), but IP still doesn't respond to pings until I power cycle. At no point have I seen the power LED "steadily blinking green" (or any colour) per the instructions. What I see when I power on the device normally is that the power LED switches to green for maybe 2-3 seconds, then switches to amber and back to green and then stays like that.

* nmrpflash: this never receives a conection. I disabled the Windows firewall and tried both going through a switch and directly to the router.

Any suggestions for how to proceed?

I haven't tried to setup a serial console yet as I assume that will require opening the unit, but with DD-WRT apparently running on the unit I'm hoping this won't be necessary.

[1] Netgear tftp: https://kb.netgear.com/000059633/How-do-I-upload-firmware-to-my-NETGEAR-router-using-a-TFTP-client-on-Microsoft-Windows

[2] ddwrt tftp: https://wiki.dd-wrt.com/wiki/index.php/Netgear_WNDR3700

[3] ddwrt tftp: https://forum.dd-wrt.com/phpBB2/viewtopic.php?p=843259#843259

[4] OpenWRT tftp: https://openwrt.org/toh/netgear/wndr3700#how_to_flash_the_firmware_to_device

[5] Failsafe mode: https://openwrt.org/toh/netgear/wndr3700?#recovery_flash_in_failsafe_mode

[6] https://wiki.dd-wrt.com/wiki/index.php/Netgear_WNDR3700#WNDR3700_v3 1

[dale_gribble39]

Seems that you are either not using the right browser or webUI upgrade is broken; Other means of flashing could be timing or lack of using tftpd32/64 with anticipation window of 1024 or 2048 bytes. The nmrpflash utility sometimes requires specific things to be done to work. You can still upgrade DD-WRT, though.

Using PuTTY or KiTTY via telnet or ssh to upgrade (to current release of) DD-WRT:

[naasking]

I will try your suggestion, thanks. Is there a reason you're linking to:

http://ftp.dd-wrt.com/dd-wrtv2/downloads/betas/2024/01-02-2024-r54682/broadcom_K3X/dd-wrt.v24-54682_NEWD-2_K3.x_mega-nv64k.bin

rather than the following which matches the actual model number of my device?

https://ftp.dd-wrt.com/dd-wrtv2/downloads/betas/2024/01-02-2024-r54682/broadcom_K3X/dd-wrt.v24-54682_NEWD-2_K3.x_mega-WNDR3700v3.chk

I'm just not sure if there's some difference I should be aware of before proceeding.

[dale_gribble39]

https://wiki.dd-wrt.com/wiki/index.php/Netgear_WNDR3700
From the above Wiki, under V3:

[naasking]

Thanks, ssh was a bust, it immediately aborted the connection once I tried to execute the write command. Telnet worked but I received this error:

[kernel-panic69]

Would've been nice to see what the .chk file produced from either webUI while tailing the syslog (tail -f /var/log/messages via telnet/ssh) or from CLI flash. Seems this device can be finnicky and lack of reporting save and except for a report on a K2.6 build in the New Build - 11/01/2023 - r53843 thread requires some attention.

Help updating Netgear WNDR3700v3 from old DD-WRT

Upgrade DD-WRT on my Netgear WNDR3700v3

latest for WNDR3700v3?

Going to email BrainSlayer and link this thread.

[BrainSlayer]

[kernel-panic69]

So, to flash an upgrade via CLI, it would be this instead, I presume: