broadcom - 16.04 Oct 10 update breaks wifi and libkmod

I've tried dozens of advices, mostly from askubuntu, about disabling secure boot, purging and reinstalling bcmwl-kernel-source, followed guide for signing bcmwl-kernel-source, tried changing bcmwl-kernel-source for fcutterb43, etc. Nothing is working. No wifi after yesterday's update.

Whenever I reboot, I see this in the consoles -- though it flashes by really fast. Whenever I install something or update/upgrade, I see this. Whenever I do anything about modprobe or install bcmwl-kernel-source, this is the culprit:

libkmod: ERROR ../libkmod/libkmod-config.c:635 kmod_config_parse: /etc/modprobe.d/local.conf line 2: ignoring bad line starting with 'drm_kms_helper'

When running $ sudo modprobe wl I get the above, plus:

 libkmod: ERROR ../libkmod/libkmod-config.c:635 kmod_config_parse: /etc/modprobe.d/local.conf line 2: ignoring bad line starting with 'drm_kms_helper' modprobe: FATAL: Module wl not found in directory /lib/modules/4.4.0-42-generic

Dell 13" 9350
BCM4350 broadcom wireless

More info per @Chili555 's request:

lspci -nnk | grep 0280 -A2

libkmod: ERROR ../libkmod/libkmod-config.c:635 kmod_config_parse: /etc/modprobe.d/local.conf line 2: ignoring bad line starting with 'drm_kms_helper'
3a:00.0 Network controller [0280]: Broadcom Limited BCM4350 802.11ac Wireless Network Adapter [14e4:43a3] (rev 08)
    Subsystem: Dell BCM4350 802.11ac Wireless Network Adapter [1028:0023]
    Kernel driver in use: brcmfmac

cat /etc/modprobe.d/local.conf

options drm_kms_helper poll=N
drm_kms_helper
options drm_kms_helper poll=N

Remove this local.conf by

sudo rm /etc/modprobe.d/local.conf

This file has a wrong format.

If you really need this setting (I have no idea why you added it), the correct format of that file is

options drm_kms_helper poll=N

You need to remove the first two lines.

Regarding the wireless adapter do not install bcmwl-kernel-source. This adapter is supported by brcmfmac in kernels 4.4+. It may be blocked by rfkill though.