[Solved] BK7231N CBU Module Smart Circuit Breaker Not Connecting to WiFi After OpenBK Flash

I received another smart circuit breaker, this time with a CBU module (rather than the BL602-based PTBLU-W module that was in my two other circuit breakers.
https://www.aliexpress.com/item/1005007234329066.html (SY2 version with power monitoring)

Now I have a weird problem: I've successfully flashed OpenBK 1.18.135 (and also 1.18.124 for comparison purposes). There is no problem at all accessing the device when it is in AP mode. But no matter what I try, I can't get it to connect to my main wifi (that every other gadget is connected to, including the BL602 devices). It will, however, connect to my cell phone when I turn on hotspot.

For comparison, the device connected perfectly to my main wifi when it was still running the original Tuya firmware, so I don't think it is a hardware issue.

Are there known issues with connecting BK7231N devices to wifi? Or particular settings that must/or must not be used in the wifi setup?

I'll post a tear down once I have the wifi working and can get the correct config.

Thanks for any help and suggestions.

Does you wifi has WPA3 enabled? I think bk7231 devices does not work with that.

WPA3-only is not supported by the general OpenBK7231 release but is by the newer-SDK "_ALT" releases

Here's what I've found that may be helpful to others:
- BK7321N connects to my cell phone hotspot when it's configured for WPA2 (only); it does NOT connect when the hotspot is changed to WPA2+WPA3
- Found an answer in the question "Could WPA2 settings block the module?" which is in the FAQ (keep scrolling down!) in the item https://www.elektroda.com/rtvforum/topic3977789.html It says to use CCMP encryption only!
- My router allows detailed configuration of all settings; I allow WPA2+WPA3 but only CCMP encryption and there's no problem connecting.

I'll experiment a little more to see what else I can discover.

- YES connection with CCMP only
- NO connection with CCMP + CCMP256
- YES connection with CCMP + GCMP
- NO connection with CCMP + GCMP + GCMP256
- NO connection with CCMP + CCMP26 + GCMP + GCMP256)

NOTE that the BL602 module connects successfully for ALL four combinations. The BL602 modules also connect more quickly than the BK7231N module. I assume both behaviors are because the wifi drivers in the SDK underlying OpenBL602 are better than the drivers in the OpenBK SDK.

Comments from other forum users gave me ideas of what to search on the forum and ideas of what to experiment with. I have a Mikrotik router which does allow all wifi settings to be controlled (enabled or disabled) individually so that helped me find what worked.