Linksys WRT1900AC
From DD-WRT Wiki
Intro
There are two models of the Linksys WRT1900: AC and ACS. Each of these comes in two versions, v.1 and v.2 All four of these are supported by DD-WRT. The Linksys WRT1200AC is very similar but only has two antennas instead of 4.
The router that I am using to test and setup is the WRT1900AC v1. These instructions will probably also apply to the other versions, but it's not guaranteed.
How to Flash
1. Follow the standard procedure described for Linksys routers. 2. There are two firmware files to download and install. Do them both; in order.
a) Firmware: factory to dd-wrt, initial installation image factory-to-ddwrt.img b) Firmware: webflash image ddwrt-linksys-wrt1900ac-webflash.bin
There is also a newer Kong build, but I haven't tried that. The DD-WRT firmware from the router database page, v3.0-r28628 std (12/29/15), is perfectly stable for me so far. Note that the only build version is the Standard sized one.