The ASUS RT-AC66U Gigabit wireless dual-band router offers 5G WiFi with a max bandwidth of 1.75Gbps across 2.4GHz/5GHz. ASUS PCE-AC66 and USB-AC53 PCI …
Now you should be able to access via web gui 192.168.1.1 and it should be DD-WRT. Upgrading Updating DD-WRT. If dd-wrt is already on the router follow these instructions. If stock firmware is on the router follow the flashing instructions. Check for recommended builds … Asus RT-AC66U Dual-band Gigabit Flashed with DD-WRT - VPN Apr 28, 2017 DD-WRT Forum :: View topic - Asus RT-AC56U
Aug 20, 2014
Here are quick instructions on how to install DD-WRT in the new Asus RT-AC66U. You can find additional info and get support here . You are going to need two files; the first is a .trx, and the second is a .bin. DD-WRT on ASUS RT-AC68U Router | Karim's Blog Nov 09, 2014
Install DD-WRT on ASUS RT-AC68U or other routers
Techdata: Asus RT-AC66U Devices with Broadcom WiFi chipsets have limited OpenWrt supportability (due to limited FLOSS driver availability for Broadcom chips). Consider this when chosing a device to buy, or when deciding to flash OpenWrt on your device because it is listed as supported. Asuswrt-Merlin - Browse /RT-AC66U/Release at SourceForge.net