I found an article that is since closed where someone had successfully installed OpenWRT on a Wavlink WN573HX1 (outdoor AX1800 AP): OpenWRT on Wavlink WN573HX1 (outdoor AX1800 AP)
I'm trying to do the same thing but have pretty limited experience with this sort of thing. Would anyone be willing to guide me in the right direction on how to achieve this? I am a coder, but mostly on the web side.
You'll need console access, which requires opening the device and potentially soldering on to the board.
You'll need to set up a build environment and be capable of building openwrt from source.
You'll need to use tftp to load the first image(initramfs-kernel) to the device in order to boot it and write the final image(squashfs-sysupgrade).
For the console, There are plenty of how-tos on the general parts of that. Specifics for this particular device: the console 'pads' are below the large top heat-sink, near the ethernet port. Remove the top heat sink for access. I've gotten away with just using pressure to hold a pin header in place long enough to load the images, but depending on your equipment you may need to solder something.
Running it without the heatsink doesn't seem to bother it, I kept an eye on the temperature during the load and flash operations and it never got even warm enough to be uncomfortable to touch.
Once you have your build environment setup, drop this patch file into openwrt/target/linux/generic/pending-5.15/ and build.
You'll need to interrupt the boot sequence via the console, and tftp boot if from the initramfs-kernel.bin file first, then use sysupgrade from there to write the squashfs-sysupgrade.bin file
If it helps, here are those two binary files I built and am using to load mine: https://file.io/Ycx7x0SiTvvd
Okay so I understood about 50% of what you said here, but I believe I'm capable of doing it with some hand holding. I have plenty of soldering experience and actually successfully soldered a control board onto a nintendo game & watch handheld, but I'm going to need a lot of help with this. Are you available over zoom for a short chat? I can also pay you for your time, if need be.
What device am I using to interface with the unit?
Hello Bro.,
Can you send us a video how you do it .. we will be very thankful for that. If you have YouTube channel or a link of video in any way.
google USB TTL at your local Amazon, it needs to be 3.3v capable.
which part is giving you guys the most trouble? the hardware part (ie taking apart, accessing the pads, interfacing with a usb/serial cable)
or the software part (setting up build environment adding patch file for the flash, compiling)
would be pretty complicated, since the patch link expired 
I've removed the board from the unit, and I have received my USB-TTL interface.
Can we start with your telling where to attach the wires? On my TTL I have the following:
3v3, TXD, RXD, GND, +5V
On the unit, I see the following:
Area 1: 5VD, DM, DP, GND
Area 2: 3.3V GND LED1 LED3
Area 3: 3.3V, RX, TX, GND
Which wires connect to where?
I'd try area 3.
GND goes to GND. TX to RXD, and RX to TXD.
Don't connect 3.3v.
Thank you, but I'm going to wait for @timeport since he's already been through this process with this same hardware.
Here is how my test model is connected. I notched the heat sink so I could replace it and still access the ports. I've ordered a 3.5mm audio jack to install for permanent access without removing the cover.
FWIW I was able to get this to flash the -factory bin and it almost worked, except the factory UI tried to retain settings and overwrote a few files that stopped it from booting.
I don't know much about the system but there may be a way to modify the first-boot actions to fix and allow this to be flashed via ui instead of having to do the console lthing.
So it looks like you're only connected to RTX, TX, and GND, correct? So no need for the 3.3v or 5v input?
Do you need to power the unit with POE while doing this?
Once I connect this to a PC in the way you've shown, what software do I use to interface?
that's exactly what you were told yesterday.
you need it powered, yes.
depends on the OS
Windows - Putty
Linux - screen, minicom, etc
@frollic Have you successfully loaded OpenWRT onto this unit?
And with my current setup, it's a pain to power it using POE. Why can't I just power it using one of the V inputs?
Frollic is correct on all items.
You'll need some sort of terminal progam. Windows I typically use putty. the serial port settings are 115200/n/8/1. the n/8/1 is always the default, but putty usually defaults to 9600 for the speed.
Here is a generic guide for putty and serial/console usage https://pbxbook.com/voip/sputty.html
btw all of this is pretty universal to AP hardware, nothing specific to the wavlink here except just the exact physical location of the connections on the board.
linux...just use screen or minicom.
screen /dev/ttyUSB0 115200
ctrl-a, "k" to exit screen
mac...idk google it
and yes you have to power it via poe. the 3.3v from the pad is designed as a source, not designed as a power input to the board.
I'm getting nothing on Putty
Something strange... if I have the TTL connected when I power the unit with PoE, the blue light does NOT come on. If I power it with PoE and THEN connect the 3 TTL wires, the blue stays on.
In neither circumstance do I get anything on my terminal when I connect. Any ideas what I'm doing wrong?
swap the Rx and Tx pins
I have that problem with mine also.
Something with the cable connected causes it to either not boot or boot differently after the first time.
It's tricky to get it quick enough to nab the u-boot loader
In what order should I connect everything, and whats my window to connect at the right time?
