Launchpad report: for all those with the same problem, please subscribe to this report I opened in Launchpad so that it can gain some traction.I've been using Ubuntu 16.04 with kernel 4.7 for some time and wifi must mostly fine, except for a few random times that the connection was lost (solved by restarting network-manager). But after upgrading to kernel 4.8, wifi simply does not work when the router is using certain channels (the connection is lost in ~1 minute cycles).On the channels it does work, I get a choppy connection that briefly stops working (packets are lost but the connection is kept up) in regular cycles.dmesg shows a bunch of intermittent brcmf_cfg80211_reg_notifier: not a ISO3166 code errors:$ dmesg | grep brcmf[    5.109218] usbcore: registered new interface driver brcmfmac[    5.109280] brcmfmac 0000:3a:00.0: enabling device (0000 -> 0002)[    5.219983] brcmfmac 0000:3a:00.0: Direct firmware load for brcm/brcmfmac4350-pcie.txt failed with error -2[    5.651605] brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Oct 22 2015 06:16:26 version 7.35.180.119 (r594535) FWID 01-e791c176[    5.672505] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)[    5.691020] brcmfmac 0000:3a:00.0 wlp58s0: renamed from wlan0[    6.755994] brcmfmac: brcmf_cfg80211_escan_handler: scan not ready, bsscfgidx=0[    6.755997] brcmfmac: brcmf_fweh_event_worker: event handler failed (69)[   78.628101] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)[  144.057646] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)[  211.640770] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)...[ 2644.643388] brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code (0x30 0x30)The wifi adapter is detected fine:$ lspci -k | grep Net3a:00.0 Network controller: Broadcom Corporation BCM4350 802.11ac Wireless Network Adapter (rev 08)    Subsystem: Dell BCM4350 802.11ac Wireless Network AdapterI tried rolling back to an older version of network-manager but nothing changed. Currently using:+++-=========================================-=========================-=========================-========================================================================================hi  network-manager                           1.1.93-0ubuntu4           amd64                     network management framework (daemon and userspace tools)Normally I would just roll back to 4.7 and wait for a fix, but kernel 4.8 fixes other issues for Skylake-based hardware which are relevant to me.EDIT I've tried Ubuntu 16.10's daily build (ships with kernel 4.8) and the exact same problem is present.
Dell XPS 13 9350 wifi dying with Broadcom BCM4350 and 4.8 kernel
ubuntu;linux kernel;wifi;broadcom