There really needs to be a FAQ for OpenWrt with this basic stuff. Never knew about this for fw upgrades. This along with 'best practice' settings for Mvebu routers for Wi-Fi settings (the biggest headache for us mwlwifi users), QoS/SQM, SFE, etc. so the same information doesn't need to be constantly repeated would be incredible.
I'd be happy to start one if I could pin it to the top of these forum threads.
SQM QOS or even QOS isn't a one class fits all, each broadband connection is completely different.
As for firmware upgrades etc information about this is here: https://openwrt.org/toh/linksys/wrt_ac_series
New wireless card is here and for the life of me i can't get 160mhz to work on the WRT32x.
Is the 160mhz width not working because "Radar Detected"? and then 5Ghz drops?
I've been able to get it working on the 3200acm, but after radar is detect it dies. This is because the width (160) crosses over into DFS territory.
Nope i change channel to 160mhz and after that 5GHZ just doesn't show up at all only the 2.4Ghz range shows up.
Soon as i place it back to 80mhz all is working again. Its wierd, will more time to test tomorrow. But now dealing with a latency issue as the AX200 has increase latency from 35ms to 122ms.
Edit: 160mhz is working now, Reflashed back to stock and then back to OpenWRT. On top of that i restored my backup file which was made today and it works, just takes longer to come up still having issues with latency on my new Wireless card but it also happens on stock so its not a firmware issue.
Upgraded from OpenWRT with my saved settings and the wifi is working.
It’s called the wiki. There’s plenty of info there, but people prefer to be spoon fed instead of searching.
There’s a permanent dent in my desk where I bang my head every time I see a new thread called “how do I revert my wrtxxxxxx to stock”.
If you see something you think should be preserved, add it to the wiki or send it to someone who can.
In my opinion while the information on tricking the system into flashing the same partition is interesting, this whole “must have an OEM safety net” thing is just a waste of time and effort. These things are so easy to recover and it rarely goes completely belly up.
I find wikis often out of date and poorly maintained, so a FAQ that IS up to date sounds like a great idea to me!
davidc502 Here's a fun question: Would the extra radio be appropriate for dual WAN failover by connecting as a client to your android phone's hotspot which is turned on automatically by macro when the NFC tag you placed on the stand is detected? Asking for a "friend" 
Extra radio doesn't work in that manner, i have tested it myself. radio2 is just a radar detector. Although you can make it display SSID's and even connect to it, its not that reliable.
I would agree and is not supported to be used in that manner.
The wiki is the place to put such information.
If someone has the time to write a FAQ in the forum, he can do so equally in the wiki.
@davidc502 Question: What's the story on normal dual wan failover package support? I see that mwan3 packages aren't included by default, but...
By this I mean dual wan unrelated to radio2.
I'm going to agree with @solidus1983 post above and add that using the 3rd radio for wifi is not supported.
@ibex-are-goats Dual WAN doesn't use Wireless it uses another Ethernet Port or USB (LTE Modems).
If you dual failover just simply install mwan3, it might not of been installed with the firmware due to space with older WRT routers being so low.
Its the whole idea with OpenWRT though install minimal items and let the end user customise the experience.
Dual WAN doesn't use Wireless
An interface is an interface, so you should have no problem doing dual wan failover with one of the radios. If you don't have a spare access point to test this with you can use the wifi hotspot on your phone! 
There are a couple relevant wiki articles you can find https://openwrt.org/docs/guide-user/network/wifi/connect_client_wifi
it might not of been installed with the firmware due to space
Well, everything a trade, but each router has its own image, and david can include what he wants in his images. For all I know there's a bug with dual wan on this router and that's why the appropriate software packages are not included. That's why I've gotta ask!
I have weaker signal on this firmware then Openwrts. Any advice? I tried 5Ghz 80mhz 36-48 channels.
Edit: I noticed my 5ghz is set to 00 - World and 2.4 set to FR? wtf? What?
Same driver and firmware, so no difference there at the moment. If you have one of the newer boxes like the acm or 32x, then power is set by chip anyway and can't be adjusted.
Either way, I'd say the weaker signal is by perception.
Sorry about that, there I go "assuming" again and not reading as well as I should, and I'll blame my current workload for that... lol
So, you are talking about using the normal WAN interface and provisioning one of the switch interfaces to provide the redundancy you need? EDIT -= "An interface is an interface, so you should have no problem doing dual wan failover with one of the radios."
No, you are talking about using one of the radio's for the failover.
But yes, I have to be careful about what I include in these builds because some of the old hardware is getting rather full on what's being provided today.
I seem to recall someone else bringing this subject up months ago, but I don't recall the outcome. I can do some searching tonight and see what I can find.
TARGET_MULTI_PROFILE && TARGET_PER_DEVICE_ROOTFS can help with that (I'm using it to build images for 4 MB up to 128 MB flash devices in a single build/ target). In the specific case of mwan3 it might cause unintended side effects if installed, but not intentionally configured though.
Weird. I have 71% signal streight on OpenWRT and 58% with davidc502.
I just wanted to share my opinion on this discussion: I'd really appreciate having mwan3 available by default.
I'm using mwan3 on WRT1200ACv2 together with a couple of additional SW installed for WAN fallback. Not having any memory issues.
Let me give some explanation why (I think) it would be very helpful in my case:
My setup has two WAN lines and two "virtual WAN" lines which are actually VPN tunnels through the "real" WAN.
I'm using a startup script which checks whether the OpenWRT version has changed on boot (ie. a reboot after a firmware update) and re-installs all additional packages that I need (but that are not included in the default FW).
At the time of reboot it's unclear which WAN line is available (and if the VPNs are already set up).
Under normal operation this is handled by MWAN3. But MWAN3 is not yet installed (after the FW update).
So depending on the current WAN "situation" (and the default route setting), the download of MWAN packages might fail and manual steps are needed to get MWAN3 working again.
I think having MWAN3 available right after FW upgrade would make the setup much more robust.
However, I don't want to say that there are other solution to my concrete problem. And surely I can understand that older hardware models might have a memory problem. So no big deal if MWAN3 can't be added by default.