BCM43438 in rpi3b only in G-mode for Russia (RU regulatory domain)

[DmAl_4630701]

I spended so many time trying to understand, why WiFi module in rpi3b working only in G-mode (speed 54 Mb/s) and not N-mode.

Tried many kernels, firmwares (cypress-firmware-v4.14.77-2020_0115.tar.gz).

But no luck.

pi@raspberrypi:~/ $ iwconfig

wlan0     IEEE 802.11  ESSID:

          Mode:Managed  Frequency:2.462 GHz

          Bit Rate=54 Mb/s   Tx-Power=31 dBm  

And today I tested another regulatory domain (not my RU for Russia):

sudo iw reg set US

And speed momentally upsters to 72 Mb/s!!

pi@raspberrypi:~/$ iwconfig

wlan0     IEEE 802.11  ESSID:

          Mode:Managed  Frequency:2.462 GHz 

          Bit Rate=72.2 Mb/s   Tx-Power=31 dBm  

Why Russian Raspberry Pi users must work only in G-mode (with speed 54 Mb/s)? 

[GauravS_31]

You are correct. For country code RU, 802.11n rates had been disabled in the CLM blob which is why N-mode does not work. But for country code US, 802.11n rates had been enabled. Changing the kernel or firmware will not alter this behaviour because the regulatory information is inside the CLM blob.