wifi not scanning network

[javacom]

I used MacBook Air 2018 and there is no wifi settings, I can only connect internet via bluetooth network.
and I do
sudo dpkg -i /usr/src/iso-firmware.deb
The Wifi-Settings does not scan any wifi station for connection.
Then I restart network service
sudo systemctl restart NetworkManager.service sudo systemctl restart iwd.service

and there are errors as
`-- The job identifier is 8973 and the job result is done.
Apr 14 15:46:10 ubuntu-mpb systemd[1]: iwd.service: Start request repeated too quickly.
Apr 14 15:46:10 ubuntu-mpb systemd[1]: iwd.service: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support

-- The unit iwd.service has entered the 'failed' state with result 'exit-code'.
Apr 14 15:46:10 ubuntu-mpb systemd[1]: Failed to start Wireless service.
-- Subject: A start job for unit iwd.service has failed
`

[AdityaGarg8]

May I know what's uname -r

[AdityaGarg8]

I'd also like to have the output of cat /etc/NetworkManager/NetworkManager.conf and cat /etc/NetworkManager/conf.d/wifi_backend.conf

[javacom]

uname -r
5.17.1-t2

cat /etc/NetworkManager/NetworkManager.conf
[main]
rc-manager=resolvconf
plugins=ifupdown,keyfile
dns=dnsmasq
[ifupdown]
managed=false

cat /etc/NetworkManager/conf.d/wifi_backend.conf
[device]
wifi.backend=iwd

[AdityaGarg8]

Edit /etc/NetworkManager/NetworkManager.conf to look like this

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=false

[device]
wifi.scan-rand-mac-address=no

and edit /etc/NetworkManager/conf.d/wifi_backend.conf to look like this

#[device]
#wifi.backend=iwd

Then run
sudo systemctl restart NetworkManager

[javacom]

Tried and restart service, even reboot still no wifi networks
It is strange that if I do
sudo iwlist wlan0 scan
some ESSID (e.g. my home network 2.4GHz only) can be listed.

For your information, MacBook Air 2018 is

lspci | grep Broad
02:00.0 Network controller: Broadcom Inc. and subsidiaries BCM4355 802.11ac Wireless LAN SoC (rev 0c)

[AdityaGarg8]

I'd also like to have the output of cat /etc/NetworkManager/NetworkManager.conf and cat /etc/NetworkManager/conf.d/wifi_backend.conf

Could you send this again so that I may confirm you did the right thing?

[javacom]

I re-install the ubuntu again and now I plug the USB Wifi Adapter which is
Bus 001 Device 003: ID 0bda:8172 Realtek Semiconductor Corp. RTL8191SU 802.11n WLAN Adapter

and the wifi adapter is not scanning at all.
the iwconfig shows
wlx48022a1a00cd unassociated Nickname:"rtl_wifi" Mode:Auto Access Point: Not-Associated Sensitivity:0/0 Retry:off RTS thr:off Fragment thr:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0

cat /etc/NetworkManager/NetworkManager.conf
[main]
rc-manager=resolvconf
plugins=ifupdown,keyfile
dns=dnsmasq
[ifupdown]
managed=false

cat /etc/NetworkManager/conf.d/wifi_backend.conf
[device]
wifi.backend=iwd

when I changed the NetworkManager.conf and backend.conf to not using iwd
and restart NetworkManager, it works now for the USB wifi Adaptor.

But the internal Broadcom BCM4355 for MacBook Air is still not working.

[javacom]

OK it is working now for the internal Broadcom BCM4355 for MacBook Air.
After I
`sudo systemctl restart NetworkManager

sudo modprobe brcmfmac`

And then reboot.