No more WIFI. oem-wifi-intel-iwlwifi doesn't build on the new 4.4 kernel

Question

i have trouble with internal wifi card on my Dell Latitude 5590 runing Ubuntu 16.04 LTS. What happend before problem occured:

1. I recieved notification that my laptop has updates, updated it, enrolled MOK (as it begged) and everything worked fine.
2. I decided to remove Code::Blocks, which resulted into this
3. Restarted pc and Ubuntu lost embedded wifi adapter

sudo lshw -C Network shows

  *-network UNCLAIMED     
       description: Network controller
       product: Wireless 8265 / 8275
       vendor: Intel Corporation

lspci -nn recognizes adapter

02:00.0 Network controller [0280]: 
 Corporation Wireless 8265 / 8275 [8086:24fd] (rev 78)

and rfkill list output is

0: dell-wifi: Wireless LAN
    Soft blocked: no
    Hard blocked: no
1: dell-bluetooth: Bluetooth
    Soft blocked: yes
    Hard blocked: no
2: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no

As far as i understood the problem is in oem-wifi-intel-iwlwifi-lp1757035-4.4-dkms-dkms, because then i try to reinstall it with sudo apt-get install --reinstall oem-wifi-intel*, it stops, signaling Bad return status for module build on kernel: 4.4.0-143-generic

Answer 1

The 4.4 kernel doesn't support your wireless adapter. That is the reason you installed some dkms module with a backport of that driver.

After a kernel update the driver doesn't build, or is blocked by Secure Boot.

I suggest removing that dkms package completely and switch to a HWE kernel that does support your wireless adapter.

First boot with the previous kernel using grub menu. Wi-Fi should work.

Then run in a terminal

sudo apt purge 'oem-wifi-intel.*'
sudo apt install linux-generic-hwe-16.04

Reboot.