This issue happens only on UEFI systems with enabled Secure Boot.

When I try to install DKMS modules like VirtualBox, Nvidia, or Broadcom drivers, they do not install and I get Required key not available when I try to modprobe them.

VirtualBox complains that vboxdrv is not loaded.

Broadcom wl driver is shown in lspci -k as a kernel module but is not in use. sudo modprobe wl throws Required key not available .

Also this issue may happen when I install some kernel modules from git sources.

This issue may appear after a kernel update as disabled wireless adapter, black screen after a reboot, etc.

How can I fix it?