Raspberry Pi 4 wireless NIC not found

Exaga · 01-02-2020, 12:25 PM

So, you have a Raspberry Pi 4 running Slackware ARM, and until recently [could be any time from kernel 4.19.69 - onwards] the wireless NIC worked fine but now it's gone AWOL or refuses to function as expected. Welcome to the [ ! so_wonderful ] perpetual world of "Oh no! The wireless NIC has stopped working again!" as it's a recurring phenomenon usually attributed to out-dated RPi firmware. If this describes your RPi4 wifi situation then there's a solution - FOR NOW! Until it stops working the next time.

With the RPi4 device connected to the network via Ethernet, as 'root' user remove the existing wireless brcmfmac driver module :

Code:

root@torq:~# rmmod brcmfmac

Download and install the latest [SARPi] kernel, kernel-modules and boot-firmware packages from: http://sarpi.fatdog.eu/index.php?p=rpi4getcurrent

Re-install the driver:

Code:

root@torq:~# modprobe -vvv brcmfmac
modprobe: INFO: custom logging function 0x19c94 registered
insmod /lib/modules/4.19.89-v7l-arm/kernel/drivers/net/wireless/broadcom/brcm80211/brcmfmac/brcmfmac.ko
modprobe: INFO: context 0xbf4328 released

Check out the WNIC inurface :

Code:

root@torq:~# ifconfig wlan0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet6 abc1::1234:abc2:1234:ab12  prefixlen 64  scopeid 0x20<link>
        ether ab:cd:ef:12:34:56  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 10  bytes 1036 (1.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

root@torq:~# ip a
4: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether ab:cd:ef:12:34:56 brd ff:ff:ff:ff:ff:ff
    inet6 abc1::1234:abc2:1234:ab12/64 scope link
       valid_lft forever preferred_lft forever

Edit wpa_supplicant.conf :

Code:

root@torq:~# nano -w /etc/wpa_supplicant.conf

Ensure your wpa_supplicant.conf looks similar to this. If not, modify it accordingly and save-quit. NB: your country-code should be NL US GB IE FR DE (etc.):

Code:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel
update_config=0
country=<your_country-code_goes_here>

Start wpa_supplicant :

Code:

root@torq:~# wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf
Successfully initialized wpa_supplicant

Use wpa_cli to setup and configure the wlan0 interface :

Code:

root@torq:~# wpa_cli
wpa_cli v2.9
Copyright (c) 2004-2019, Jouni Malinen <j@w1.fi> and contributors

This software may be distributed under the terms of the BSD license.
See README for more details.

Selected interface 'wlan0'

Interactive mode

> scan
OK
<3>CTRL-EVENT-SCAN-STARTED

> scan_results
bssid / frequency / signal level / flags / ssid
ef:7c:5b:3d:1a:11       2412    -33     [WPA-PSK-CCMP+TKIP][WPA2-PSK-CCMP+TKIP][WPS][ESS]       EXAGA2G
ef:7c:5b:3d:1a:12       5180    -41     [WPA-PSK-CCMP+TKIP][WPA2-PSK-CCMP+TKIP][WPS][ESS]       EXAGA5G
4c:38:d8:03:6e:21       2437    -58     [WPA-PSK-CCMP+TKIP][WPA2-PSK-CCMP+TKIP][WPS][ESS]       VM2077355
2a:35:d1:60:92:19       2447    -59     [WPA2-EAP-CCMP][ESS]    Virgin Media

> add_network
0
> set_network 0 ssid "<your_network_SSID_goes_here>"
OK
> set_network 0 psk "<your_wifi_password_goes_here>"
OK
> enable_network 0
0K
> quit

Enable the wlan0 interface and assign it an IP address and netmask. NB: This is only an example - you must fill in your own IP address and netmask here :

Code:

root@torq:~# ifconfig wlan0 192.168.1.123 netmask 255.255.255.0 up

Now check to see if what you've done has brought your RPi4 wireless NIC back to life :

Code:

root@torq:~# ifconfig wlan0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.123  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 abc1::1234:abc2:1234:ab12  prefixlen 64  scopeid 0x20<link>
        ether ab:cd:ef:12:34:56  txqueuelen 1000  (Ethernet)
        RX packets 225  bytes 17398 (16.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 426  bytes 56265 (54.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

So, the wlan0 interface shows that it's up and configured correctly [or should do!]. Now you can disconnect the Ethernet cable and check that the new wireless connection is working as expected :

Code:

root@torq:~# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=55 time=22.5 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=55 time=24.0 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=55 time=19.5 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=55 time=20.8 ms
^C
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 19.541/21.687/23.967/1.674 ms

If your wireless still isn't working after all that, go back and try again. Prudent advice would be to open a packet of Jaffa cakes when facing any Slackware issues, for greater success and more satisfying result purposes.

*** No Slackware ARM packages were harmed during the creation of this LQ forum post.

kermitdafrog8 · 01-02-2020, 12:33 PM

Thanks for all you do.

Exaga · 01-03-2020, 04:14 AM

Quote:

Originally Posted by kermitdafrog8

Thanks for all you do.

Thank you more. You're too kind. It's a pleasure to share Slackware knowledge and experience(s) on any platform or device. I wish there were a lot more users doing it.

Real thanks go to Patrick for this wonderful OS, and MoZes for his ceaseless ARM alchemy. I'm just a simple messenger.

kermitdafrog8 · 01-03-2020, 01:41 PM

Yes. Thanks to them for everything. I wish I could do more for Slackware.