Takes multiple attempts to connect 5GHz AC Wireless

OS: Ubuntu 14.04 LTS (dual boot with Windows 8.1)

Hardware: HP Spectre x360 - 13-4002dx

Network: Intel Wireless-AC 7265

Driver: iwlwifi

Driver Version: 3.16.0-56-generic

When I boot into Ubuntu (regardless of last boot being Windows/Ubuntu), it takes me several (over a dozen) attempts to authenticate to my wireless-AC router. I have the password stored, so I just keep hitting connect over and over again (5-6 second delay between prompts). Eventually it will connect. This doesn't happen with Windows. This also doesn't happen if I connect to the 2.4 GHz band on the same exact router - only with 5 GHz.

Like I said, it will eventually connect, but it is annoying to have to keep trying. Any ideas what could be causing this, or how to fix it?

1 Answer

First, check the settings in the router. WPA2-AES is preferred; not any WPA and WPA2 mixed mode and certainly not TKIP. Second, if your router is capable of N speeds, you may have better connectivity with a channel width of 20 MHz in the 2.4 GHz band instead of automatic 20/40 MHz, although it is likely to affect N speeds. I also have better luck with a fixed channel, either 1, 6 or 11, rather than automatic channel selection. Also, be certain the router is not set to use N speeds only; auto B, G and N is preferred. After making these changes, reboot the router.

Next, I recommend that your regulatory domain be set explicitly. Check yours:

sudo iw reg get

If you get 00, that is a one-size-maybe-fits-all setting. Find yours here: Then set it temporarily:

sudo iw reg set IS

Of course, substitute your country code if not Iceland. Set it permanently:

gksudo gedit /etc/default/crda

Use nano or kate or leafpad if you don't have the text editor gedit.

Change the last line to read:

REGDOMAIN=IS

Proofread carefully, save and close the text editor.

Next, I'd set IPv6 to Ignore in Network Manager: This example is for ethernet, but you want wireless.

If these changes do not help, please try:

sudo modprobe -r iwlwifi
sudo modprobe iwlwifi 11n_disable=8

If it helps, make it permanent:

sudo -i
echo "options iwlwifi 11n_disable=8" >> /etc/modprobe.d/iwlwifi.conf
exit

Finally, Network Manager will default to ethernet if it's available. Please make your tests with the ethernet detached.

Next, I suggest you install the backports package:

sudo apt-get update
sudo apt-get install linux-headers-generic build-essential
wget
tar -zxvf backports-20151120.tar.gz
cd backports-20151120
make defconfig-iwlwifi
make
sudo make install

Now we need the latest firmware.

sudo apt-get install git
git clone
cd linux-firmware/firmware
sudo cp iwlwifi-7265D-14.ucode /lib/firmware
sudo cp iwlwifi-7265D-15.ucode /lib/firmware

Reboot and check:

dmesg | grep firmware

Ideally, the -15 firmware is loaded and performance is greatly improved.

If this helps, you will need to recompile every time Update Manager installs a later kernel, known as linux-image. After the requested reboot, recompile:

cd backports-20151120
make clean
make defconfig-iwlwifi
make
sudo make install

Please retain the file and these instructions for that time.