I have NUC 7PJYH with Intel wireless AC-9462 card. The problem is that systems randomly freezes when using WiFi. There are no freezes when wifi is disabled. I tried to use different kernels, but still the same behaviour.

I investigated dmesg when I was on kernel 4.16.12 and I found that the kernel is asking for iwlwifi-9000-pu-b0-jf-b0-35 and iwlwifi-9000-pu-b0-jf-b0-36 firmware files. I tried to find these files on wireless.wiki.kernel.org. I went through all repositories they maintain and I found only versions 34 and 38 of this firmware.

Where can I find the correct firmware for kernel 4.16? These files are not even in the official linux-firmware package tree.


wifi related dmesg output:

[    3.476177] iwlwifi 0000:00:0c.0: enabling device (0000 -> 0002)

[    3.483822] iwlwifi 0000:00:0c.0: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-36.ucode failed with error -2

[    3.483839] iwlwifi 0000:00:0c.0: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-35.ucode failed with error -2

[    3.497077] iwlwifi 0000:00:0c.0: loaded firmware version 34.3125811985.0 op_mode iwlmvm

[    3.570636] iwlwifi 0000:00:0c.0: Detected Intel(R) Dual Band Wireless AC 9462, REV=0x318

[    3.624572] iwlwifi 0000:00:0c.0: base HW address: 68:ec:c5:9c:38:3f

[    3.685419] ieee80211 phy0: Selected rate control algorithm 'iwl-mvm-rs'

[    3.974259] iwlwifi 0000:00:0c.0 wlo1: renamed from wlan0

[    4.856976] iwlwifi 0000:00:0c.0: Conflict between TLV & NVM regarding enabling LAR (TLV = enabled NVM =disabled)
  • I would like to add that the error message about missing firmware is not there with kernel 4.15 because it uses iwlwifi-9000-pu-b0-jf-b0-34 which is available in 18.04. But system hangs as I wrote in the original post. That is the reason I'm trying to upgrade kernel. May 26, 2018 at 10:32

1 Answer 1


I believe that the reason that you nor I can find any x.35 or x.36 firmware with a thorough web search is that they don't yet exist. The driver in question, iwlwifi, is written to look for the latest firmware version first; failing to find it, look for the next latest and so on until a suitable firmware file is found.

At the same time, the driver is written to automatically use later firmware versions as they are developed and included in newer versions of linux-firmware. In other words, when x.35 is written and released, the driver iwlwifi will find and use it without the necessity of a newer version of the driver. This is quite common in Intel and some other wireless drivers.

I think there is some reason other than firmware that causes your system to hang when using wireless. I invite you to ask a new open-ended question and include: dmesg | grep -e iwl -e wlp.

EDIT: We see this clue in your dmesg:

Conflict between TLV & NVM regarding enabling LAR (TLV = enabled NVM =disabled)

I suggested that you try a driver parameter:

sudo modprobe -r iwlwifi && sudo modprobe iwlwifi lar_disable=Y

It seems to have solved the hang issue so I suggest that you make it permanent:

sudo -i
echo "options iwlwifi lar_disable=Y"  >>  /etc/modprobe.d/iwlwifi.conf

You should be all set.

  • Thank you for your answer. I saw in the log that x.34 was used instead, so I'm using still the same firmware with different kernels. What is confusing is that I was able to find x.38 of this firmware; but as you wrote, x.35 and x.36 have not been released yet. May 26, 2018 at 14:52
  • I believe, based on using and studying Intel wireless devices exclusively for about 15 years, that the very high firmware numbers like x.38 that are not even referenced in the driver; e.g. modinfo iwlwifi | grep firm are experimental, bleeding edge firmware versions.
    – chili555
    May 26, 2018 at 15:06
  • Thanks for explanation. I added my dmesg output into the original question. So I will wait for new kernel/firmware because I believe there must be some bug. What is weird is that system hangs only when streaming video e.g. from youtube. My first guess was GPU issue, but as I wrote, it works perfectly on wired network. May 26, 2018 at 15:18
  • 1
    Please try: sudo modprobe -r iwlwifi followed by: sudo modprobe iwlwifi lar_disable=Y and test. If it helps, I'll add it to my answer, making it persistent.
    – chili555
    May 26, 2018 at 15:37
  • 1
    Testing it 10 minutes and so far so good. I usually saw system freeze in less than one minute when streaming video. It seems you solved my problem! How come this helped? May 26, 2018 at 15:52

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