I installed Ubuntu on a new macpro and was hoping things would go well until I saw that there aren't any wifi drivers installed (Broadcom 4331 if I'm not mistaken). I went as far as installing b43-fwcutter and managed to extract the firmware out of wl_psta.o into a folder but unable to copy it to /lib/firmware/b43 given I don't have root permissions (but I thought I did using sudo -r command?).

I'm new to a lot of things here and was hoping someone could provide some assistance, any help would be appreciated.

Thanks!