"ls: cannot access sys/class/ieee80211: No such file or directory" .

1- Do update and upgrade as always.

apt-get update && apt-get upgrade && apt-get dist-upgrade -y

2- Install headers.

apt-get install linux-headers-`uname -r`

3-Install synaptic.

apt-get install synaptic -y

4-Open synaptic and type "bcm43142" and search.

5-U'll see 3 different drivers.

broadcom-sta-common
broadcom-sta-dkms
broadcom-sta-source

6-Mark for installation to broadcom-sta-dkms and install it. 

7-Reboot.
Read more at https://www.inforge.net/xi/threads/ls-cannot-access-sys-class-ieee80211-no-such-file-or-directory.454606/#jT8ThY4bq4BrwUHh.99

安装后依然没有解决....

但是不必担心，在挂载成功无线网卡后，并没有任何影响。