Or read the WNDR3700 wiki and upgrade via TFTP, which then you would use the file you linked wndr3700-factory.img for TFTP'n Ok. I tried the webflash version the first time i flashed the routed and it was semi-bricked.

Nov 26, 2014 DD-WRT Forum :: View topic - Netgear WNDR3700v4 (dd-wrt Jun 04, 2016 Amazon.com: Customer reviews: Netgear N600 Wireless Router

Sep 27, 2017

Upgrade to newest version android firmware on you device, netgear wndr3700 firmware update update you current version android firmware to latest version, download newest android firmware | Download & update android firmware updated 20 Jul 2020 10:10 openwrt-ramips-mt7621-netgear_r6800-squashfs-sysupgrade.bin: Should be used when you want to upgrade openwrt firmware from openwrt firmware. It supports basic features. I would be happy to get your feedback about it and what features you want to see in next version of this firmware. Upgrade to newest version android firmware on you device, netgear n600 wndr3700 firmware update update you current version android firmware to latest version, download newest android firmware | Download & update android firmware updated 20 Jul 2020 10:10

Netgear sucks! Update 1: ok, I head this over a month now. a couple more things to add. i dont like netgear as a company. this router is pretty stable for me, but the firmware, the admin console has a few bugs and inconveniences, and it seems netgear doesn't really respond to fixing them all that quickly.

DD-WRT Forum :: View topic - Netgear wndr3700 (v1.0.7.98 Mar 01, 2019 DD-WRT Forum :: View topic - Netgear WNDR3700, not Sep 05, 2011 DD-WRT Forum :: View topic - wndr3700-webflash