DIR-885L A2, 5GHz not working

I have several DIR-885L routers, two A1s and three A2s. I've only just recently tried to install OpenWrt on any of them. I started by installing it on an A1, with which I'd recently started to have issues. Specifically, the 2.4Ghz and 5GHz stopped working. I figured if I bricked it, no big loss.

@panomitrius I've now flashed one of my A2s with OpenWrt 19.07.7 and immediately got the 2.4GHz radio configured and working. I'm using the (brcmfmac4366c-pcie) firmware suggested in the guide, and can confirm that no .txt file is required. Initially I had problems getting the 5Ghz radio to work. I found that it would switch to Client mode, even though it had been set to AP mode. The problem appeared to be associated with the Channel "auto" option. As soon as I selected Channel 44, it worked. I suggest not using the Channel "auto" option, and try different channels until you find one that works.

I've found that some of the 5GHz channels don't work. Once I have a complete list of what works, and doesn't, I'd like to file a bug report (if someone would kindly point me to the appropriate location).

@yfwwangyue As mentioned above, I started down this "rabbit hole" by flashing an A1 which had wireless issues. With OEM firmware installed neither radio worked. However, once I flashed it with OpenWrt, I got the 2.4GHz radio working. As you've only posted a portion of your logs, it's hard to see what's going on. However, if you're not getting the following message, it's likely a hardware problem. I'd suggest reverting to the OEM firmware to confirm that everything is working properly, then try flashing OpenWrt again.

pcie_iproc_bcma bcma0:8: link: UP

@panomitrius My apologies! I re-read your initial post shortly after posting mine. It was only then, to my horror, that I realized that mine appears as if I had not read yours at all. I know how frustrating that can be. I can assure I've read this thread several times, but at the time when I was focused on getting the 5GHz radio working on my own router, and not on helping someone else.

insert_sound ( ) {
echo "palm of hand being applied firmly to forehead"

Although you mentioned that you could not get the Channel "auto" option to work, and tried setting it manually to a "lower channel", you did not indicate the specific channels you'd tried. Since posting my reply, I've done some additional research, which may be helpful.

The first thing I've noticed is that the OEM firmware only allows this router to be set to Channels 36, 40, 44, 48, 149, 153, 157, 161 and 165, regardless of hardware version. I'm in Canada, so this is with the Country Code set to "CA". Furthermore, this does not appear to be unique to this make or model of router. The OEM firmware for the Linksys EA9500, which also uses the Broadcom BCM4366, also limits its 5GHz operation to these nine channels. Note that these are all 20MHz wide channels, so changing the channel width should have no effect on performance.

Next, to keep us out of jail, OpenWrt/LuCI uses the CRDA database, which contains the wireless regulatory details for each country. Basically, it uses this database to lookup which channels, power levels, etc., are legal to use in a particular country. Unfortunately, this is a one size fits all type of solution for firmware that's intended for use with a great many makes, models, versions, and types of hardware (please, this is simply intended as an observation; not a criticism). I understand that OpenWrt/LuCi is trying to deal with a very complicated issue, and contains a great many moving parts. So, the take away from this should be that, even if you have OpenWrt/LuCI configured correctly, and the correct working driver installed, you should NOT expect every channel listed to work. This depends entirely on the hardware you're using, which may only support a subset of those legally allowed, etc.

Also, the Channel "auto" option appears to select the first legal channel, not scan for the one that is least congested. In this case, it will select a channel that doesn't appear to be supported by the hardware.

Finally, I found that with OpenWrt/LuCI (19.07.7) installed I can only get Channels 36, 40, 44 and 48 to work on my A2 router. I've checked that these channels work with the OEM firmware installed, but haven't had a chance to see if this is also an issue with A1 hardware. Unfortunately, the only working A1 I have is currently in use.

QUESTION: Does anyone have Channels 149, 153, 157, 161 or 165 working with OpenWrt/LuCI installed? Please indicate the hardware version (A1 or A2).

Thanks for your thorough reply @lwbeam! I actually decided it was too much of a hassle to get this to work, so I sold the A2 router and got myself a Netgear R7800 instead. Hope this will help anyone else running into problems!