A while ago I got hold of a couple of DLink DIR-865L AC1750 802.11ac routers as there was a generous cashback offer.
I was originally using it as a glorified access point, but since updating my main router to carve off a variety of ethernet segments for home automation, guest networks, etc, I wanted to expose these as different wifi networks, using the DIR-865L units to extend the wifi network, with ethernet backhaul to the main router.
To get OpenWRT onto the router (where the router's IP is 10.0.1.200 and the tftp server is 10.0.1.16):
- Download the OpenWRT TRX file
- Make the file available on your tftp server
- Connect to the serial port on the unit (see below), 115200,8,N,1
- Hit Control-C while the bootloader is running to get to the CFE prompt
- Set the IP address of the machine: ifconfig eth0 -addr=10.0.1.200 (docs)
- Flash the firmware: flash -noheader 10.0.1.16:openwrt-brcm47xx-mips74k-squashfs.trx flash0.trx
To get to the serial port on the machine:
- Unscrew the base of the unit and a single black screw on the rear panel.
- Gently pry the right hand side panel off (when looking at it from the front). Start with the snap clips visible through the top vent, and work your way around.
- Solder wires into the serial header. When viewed from the front of the machine, the order from left to right is TX, Ground, +3.3V (you gonerally don't need to connect this), RX.
- Optionally, clip away some of the casing from the base and glue in (I used PCL, aka Polymorph) a miniUSB-B -> USB-A adapter, and install the USB -> TTL serial adapter internally.