I installed Ubuntu 22.04 into an old Dell D620 that I bought last year just to run DOS and use the parallel port (in the Dock station) to remove the password from some Motorola Pagers.

Initially the b43 module was reporting that firmware file wasn’t found. Then I installed it:

$ sudo apt install firmware-b43-installer

Then when I run modprobe b43 again the WiFi worked, but after reboot nothing happened.

I already added b43 to /etc/modules this way:

# echo b43 >> /etc/modules

But after reset it never load b43.

So I enter inside /etc/modprobe.d and grep for b43 and noticed it was blacklisted.

After removing it:

# rm /etc/modprobe.d/blacklist-bcm43.conf

Everything worked fine in next reboot.