Uploading Firmware to "bricked" Netgear WNDR3800 from Linux with atftp after botched DD-WRT Firmware Upgrade.

The Netgear will only accept the original Netgear FW using this TFTP procedure.
All attempts loading DD-WRT this way will look like success from the TFTP Client point of view but Router will ignore it.

Original Netgear Instructions for Windows are here:
https://kb.netgear.com/22688/How-to-upload-firmware-to-a-NETGEAR-router-using-TFTP

If you want to Flash the DD WRT FW later, you need to recover to the Netgear FW Version WNDR3800-V1.0.0.16.img as later versions are blocking the DD WRT FW Upload on WebInterface.

Set the PC to 192.168.1.x/24  but not .1 as this will be router in the recovery mode.

Power Off the WNDR3800.
Hold the RESET Button and power On the Router.
Watch the Power LED Flashing Amber and then changing to Green, Count at least 10 Green Flashes and Release the RESET button. Try to ping the Router at 192.168.1.1
if you do not see any Ping replies, wireshark it and you might see the replies only in the packet trace, still good.

Then upload the FW with tftp client. Router has default password:password

[risko@t520 ~]$  atftp -p -l /home/risko/Downloads/WNDR3800-V1.0.0.16/WNDR3800-V1.0.0.16.img -P password --verbose 192.168.1.1
Option password = password
Verbose mode on.
[risko@t520 ~]$

On successful flash the power led will stop flashing and will remain off.
1 minute later the power led will be flashing alternating between amber and green followed by proper boot.


Now if you want to continue to DD WRT you find the WNDR3800 in the Router DB and there is a link for "WND3800 Firmware - Webflash image for first installation" wndr3800-factory.img

And load the firmware using the Netgear Web Interface. Username:admin Pass:password

Trying to load normal wndr3800-webflash.bin over the original Netgear 1.0.0.16 Web Interface will fail.