Wrt3200acm wifi no longer running

I've got a couple of wrt3200acm devices that no longer have a 3rd working wifi after recent upgrades (21.01 latest, not 21.01 rc which worked for me last). I know the marvell chipset is no marvel but ive always been able to use the 3rd 2g/5g chip as a guest wifi at low speeds.

I cannot get the 3rd wifi to change from this state once configured,enabled, and started:
Current power: 0 dBm

I'm using a test environment with straight stock values except enabling and changing the wificard3 channel and wpa2 password because I think the marvell chipset hates the 'option channel auto' value and I want the encryption to be wpa2 or higher.

Is 21.01 a typo as it is not listed here? Try version 21.02.1 or roll back to 19.07.8. Don't forget to update twice (this is a dual boot router).

Have you tried typing iw list? It will show your wifi chip capabilities. For example, setting to an incompatable channel will result in the device failing to start.There may be a setting that your wifi chip does not support.

Perhaps there is a solution for your 3rd wifi issues here.

It is also possible to set up a guest wifi with your 1st 2.4g wifi as detailed here. Throttle the speed on the device with luci-app-sqm.

hey there,
I meant 21.02.1. I figured out the problem and how to replicate it and also made my own workaround by simply booting to the alternative partition which was an older 21.02.1 I had not updated.

If you install a new 21.02.1 on these 3200acm devices, you can set radio2 (Marvell 88W8887 802.11nac) as a wpa2 access point changing the mode to AC, the channel to auto, and the width to 80MHz. once you reboot you can connect to it and it'll give you a power output. Mine was Current power: 8 dBm

If you run the command opkg update && opkg install hostapd-common and reboot, boom, no more AP mode at all on that wifi interface. 2.4 or 5 ghz.

This was the upgrade info I pulled on it.
hostapd-common - 2020-06-08-5a8b3662-35 - 2020-06-08-5a8b3662-37
I'm going to stick with 2020-06-08-5a8b3662-35 for now.

I hope this helps someone.
Thanks for your assistance.