This is honestly about as far as I've gotten. I tried flashing the unit with the openwrt-21.02.1...factory.bin (from the firmware downloads page) using the devices own "Upgrade devices firmware." button, but it rebooted back to factory defaults. Glad it's not bricked!
I requested Wiki access so I can update the wiki when I do figure out how to install OpenWrt.
Any advice is welcome. Last time I used OpenWrt was probably 20 years ago. I'm afraid my brain is a little less plastic, but I'm still learning!
In the git-commit I found an Installation Instructions section that says the factory firmware must first be updated to at least 1.1. My router had version 1.0.3 on it.
I found Alfa's Firmware Downloads and flashed the firmware to FW_AP120C-AC_v1.2_20190521_AP120C_AC.img. It did not automatically refresh the page after updating. For reasons I don't know I had to disconnect my ethernet connection to the router and reconnect before I could once more access the web console. Also, just for fun the default login had changed from root : alfa to root : admin.
Phew! Ok, now I'm going to try flashing OpenWrt again. ... annnd... It didn't work. The device rebooted and still shows up with the Alfa logo and shows firmware v1.2 r2457
Maybe I should try upgrading to the latest official Alfa firmware FW_AP120C-AC_v2.0-r2768_20201202_alfa.img
Yes, please try updating to 2.0 first.
The problem might be outdated bootloader, let me know if that helps, otherwise I will provide you an image with upgraded bootloader.
Several websites say there is an RJ45 console port... I have a generic cable... There are also what appears to be debugging contacts, probably JTAG, on the circuit board. Might take me a while to figure this out. Not something I do daily, but yes I think I can.
Doe! I actually wanted to get the AP120C, so it seems I bought the wrong device. Thank you for pointing this out. I had noticed that the device I had seemed to be using different chips. - I'll still try to get OpenWrt running on this device. Thank you for getting the wiki updated.
Edit: Ha! I didn't buy the wrong one. The item was advertised as the AP120C, but they sent me a AP120C-AC. What a world, what a world.....
The pads on the board that I thought might be a serial console port: are not. I'm pretty sure it's an unpopulated audio jack. I think the 20 pads in the middle of the board might be a JTAG port.
I've never used JTAG before.
I ordered a set of pin headers and a JTAG, uh, reader? It will be maybe 2-weeks until they arrive.
Forget about the JTAG. Without access to software and configuration files you won't be able to use it... the serial console connector is on the other side of the board (your photo shows the "back", console header, labelled as CONN3, is located on the "top" side). The only problem is the smaller connector pitch size - 2.0 mm, not the usual 2.54 mm:
I've been attacking windmills... I was finally successful in connecting to the serial port. I made quite a few mistakes, and learned some lessons, some not for the first time. I wrote about finding the right USB to Serial device on my blog, if anyone cares.
I loaded the firmware you sent; and I had problems connecting to the device afterward. Unfortunately I'm not sure if it was a PEBCAK error, or if something was really wrong. Using the serial console I was able to spam "f" which is supposed to trigger a failback/failsafe state. After that I could connect, and I was able to successfully load the OpenWRT firmware!
Victory! - Now I get to learn how to use OpenWRT. Time to do some more reading.
Thank you so much for your help!
Glad it's not bricked!
Time to do some more reading.