can't turn off AP mode with RPi4

[yannig]

Hello

I have a strange pb, I can't turn off the AP Mode is more than 1 meter from my wifi router.
I tried 2 different RPi4s : same pb.

It works flawlessly with Rpi 3B and 3B+

The Dac attached is the Allo Boss.

Any idea ?

I suspect a different position of the wifi antenna on the RPi4, and perhaps wifi radiation pb with the dac that I use.

An idea is perhaps to use an USB wifi antenna (but I never done this !), or came back to 3B+

[Tim Curtis]

I have a 4 + Boss and I don't recall experiencing any WiFi issues.

There is a VLI firmware update for the 4 that I had applied but I'm not sure it contained any WiFi fixes. It was mainly for improving power consumption and reducing heat.
https://www.raspberrypi.org/forums/viewt...p?t=250990

One way to troubleshoot is to first get a good WiFi connection then connect an ethernet cable, then move the Pi farther than 1 meter away from the Router when it apparently loses WiFi connectivity. At this point since you should be connected via Ethernet you could examine /var/log/syslog, dmesg and your Router WiFi logs to see if there is any clue as to what might be happening.

Another option is to install the latest Linux kernel. moOde 641 ships with 4.19.83 and the latest is 4.19.97. There have been a zillion bug fixes between these two releases. https://github.com/Hexxeh/rpi-firmware/commits/master

[yannig]

Hello Tim

thank you for your response !

I tried to update the kernel (to 4.19.97-v7l+ #1293), and at first, I seems to work.
But from the moment I moved the Rpi away from the router, the wifi connection stopped to work, even when I put again the Rpi close to the router.
(the raspberry Pi 3B wifi quality is : 63%, level -66 dBm at around 6 meters)

Now, each time I reboot the Rpi4B, it switches to AP mode, even with the RPi4B very close to the router !
(ethernet connection works).

I don't know what to try now...

[Tim Curtis]

U won't b able to troubleshoot until u connect Ethernet cable as I recommended. Then after WiFi fails u can ssh in and see the logs, examine the Network Config screen to see WiFi signal strength etc, etc

[yannig]

U won't b able to troubleshoot until u connect Ethernet cable as I recommended. Then after WiFi fails u can ssh in and see the logs, examine the Network Config screen to see WiFi signal strength etc, etc

The pb is that I can't get a wifi connection on my local network, even with a distance of 10cm between the RPi and the router.

I'll try (again) to flash the microSD card.

[yannig]

Hello

I just tried without the Allo Boss HAT Dac, and it works flawlessly !
link quality : " 76%, level -57 dBm"

Like I suspected at first, the Allo Boss makes some kind of shielding around the integrated wifi antenna (I saw this somewhere, with another combo).

This thing is crazy, and it looks like there is no way to resolve the problem.

pffff.

[yannig]

I just try a Rapsberry Pi 3 B+ I had in stock, and it works well WITH the Allo Boss.

My conclusion is still that there is a wifi pb with the combo RPi4 + Allo Boss + moOde (I didn't try another OS) + (perhaps) my router.

[yannig]

I think I had this kind of problems :

https://www.raspberrypi.org/forums/viewt...e&start=25
https://www.raspberrypi.org/forums/viewt...p?t=254640

[Tim Curtis]

The links are referring to certain HDMI monitor modes causing RF interference in the WiFi bands.

Did you have an HDMI monitor connected to the 4B ?

[yannig]

The links are referring to certain HDMI monitor modes causing RF interference in the WiFi bands.

Did you have an HDMI monitor connected to the 4B ?

non, but I suspect the Allo Boss to make some shielding problems