When I run a kernel or NVIDIA driver update on my 16.04, this triggers an initramfs rebuild which outputs the warning below:

Processing triggers for initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-34-generic
W: Possible missing firmware /lib/firmware/i915/skl_guc_ver6.bin for module i915_bpo

I have a notebook with two graphics chips, an NVIDIA GeForce 940M and the Intel i5-6200U's integrated graphics.

The device in use is my NVIDIA card:

$ inxi -G
Graphics:  Card-1: Intel Sky Lake Integrated Graphics
           Card-2: NVIDIA GM108M [GeForce 940M]
           Display Server: X.Org 1.18.3 driver: nvidia Resolution: 1920x1080@60.03hz
           GLX Renderer: GeForce 940M/PCIe/SSE2 GLX Version: 4.5.0 NVIDIA 367.35

Here's the output of lshw -c video, corresponding to my Intel graphics chip which should use that driver:

         description: VGA compatible controller
         product: Sky Lake Integrated Graphics
         vendor: Intel Corporation
         physical id: 2
         bus info: pci@0000:00:02.0
         version: 07
         width: 64 bits
         clock: 33MHz
         capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
         configuration: driver=i915_bpo latency=0
         resources: irq:125 memory:a2000000-a2ffffff memory:b0000000-bfffffff ioport:5000(size=64)

The file in the warning does not exist, only those:

$ ll /lib/firmware/i915/
total 336
drwxr-xr-x  2 root root   4096 Aug 11 13:24 ./
drwxr-xr-x 74 root root  32768 Aug 11 13:24 ../
-rw-r--r--  1 root root   5872 Jul 21 17:03 bxt_dmc_ver1_04.bin
-rw-r--r--  1 root root   5872 Jul 21 17:03 bxt_dmc_ver1_05.bin
-rw-r--r--  1 root root   8380 Jul 21 17:03 bxt_dmc_ver1_06.bin
-rw-r--r--  1 root root   8380 Jul 21 17:05 bxt_dmc_ver1_07.bin
lrwxrwxrwx  1 root root     19 Jul 21 17:05 bxt_dmc_ver1.bin -> bxt_dmc_ver1_07.bin
-rw-r--r--  1 root root   8824 Jul 21 17:03 skl_dmc_ver1_23.bin
-rw-r--r--  1 root root   8928 Jul 12 21:33 skl_dmc_ver1_26.bin
lrwxrwxrwx  1 root root     19 Jul 12 21:33 skl_dmc_ver1.bin -> skl_dmc_ver1_26.bin
-rw-r--r--  1 root root 109636 Jul 21 17:03 skl_guc_ver1_1059.bin
lrwxrwxrwx  1 root root     21 Jul 21 17:03 skl_guc_ver1.bin -> skl_guc_ver1_1059.bin
-rw-r--r--  1 root root 128320 Jul 21 17:03 skl_guc_ver4_3.bin
lrwxrwxrwx  1 root root     18 Jul 21 17:03 skl_guc_ver4.bin -> skl_guc_ver4_3.bin

The latest driver package seems to be installed though:

$ apt-cache policy xserver-xorg-video-intel
  Installed: 2:2.99.917+git20160325-1ubuntu1
  Candidate: 2:2.99.917+git20160325-1ubuntu1
  Version table:
 *** 2:2.99.917+git20160325-1ubuntu1 500
        500 http://ftp.uni-stuttgart.de/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status

What does this warning mean exactly and how can I fix it?

  • 3
    I got W: Possible missing firmware /lib/firmware/i915/kbl_dmc_ver1.bin for module i915_bpo and my CPU is SKylake with Intel HD in it. – Csaba Toth Oct 15 '16 at 17:20
  • Additionally, I'm using the 1.158 version of the linux-firmware package instead of the mainline 1.157 because only that provided working firmware for my wifi (killer wireless). – Csaba Toth Oct 15 '16 at 17:24
  • 3
    @CsabaToth kbl stands for Kabylake, which is the successor of Skylake. As you don't have such a CPU, you can either ignore the warning, or just install the Kabylake driver from the same link given in Doug Smythies' answer. – Byte Commander Oct 15 '16 at 17:49
  • Correct, i7 6820hk is just SkyLake, Kaby Lake is the next gen – Csaba Toth Oct 15 '16 at 17:56

The driver package is somewhat lagging the kernel. In my case the missing firmware doesn't matter because I don't have a SkyLake processor, but in your case it might matter. You can get the newer firmware from here.

EDIT 1: Note the link changed, but readers should still be able to find what they need in the new link, although sometimes it can be difficult to know exactly what your are looking for.

EDIT 2: This answer should be applicable to some other new firmware requirements that have come along since this answer was originally written. For example:

W: Possible missing firmware /lib/firmware/i915/kbl_dmc_ver1_01.bin for module i915
W: Possible missing firmware /lib/firmware/i915/kbl_guc_ver9_14.bin for module i915
W: Possible missing firmware /lib/firmware/i915/bxt_guc_ver8_7.bin for module i915
  • 3
    I installed both GuC and DMC drivers for Skylake successfully and I think the warning should be gone now. Thanks. – Byte Commander Aug 29 '16 at 19:06
  • 4
    Ah, I found it. Looks like the new kernel update added support for the new Kabylake Intel processors and now it would also like to have a module driver for those. Probably it's superfluous as I don't have a Kabylake CPU, but just to get the warning away, I also downloaded and installed the kbl DMC driver from the site you linked. It looks fine again now. – Byte Commander Aug 29 '16 at 19:33
  • 2
    What does "matter" mean? Will the new kernel not be able to boot or is there no real visible impact besides some warning messages? – musiKk Dec 2 '16 at 7:28
  • 3
    @musiKk: If your processor is not one that needs one of the missing firmware files, then it doesn't "matter", meaning there will be no consequence due to it being missing. For example only a Skylake processor would need the "skl" firmware. – Doug Smythies Dec 2 '16 at 14:50
  • 1
    @FeryArdiant: Yes, the warnings are not related to which processor you are actually using, just if you have the firmware or not. – Doug Smythies Dec 15 '16 at 1:34

April 8, 2019 Update

Sometime ago (not sure exactly when) Canonical made it easier to update Linux i915 drivers in Ubuntu. Try this command first:

sudo apt install --reinstall linux-firmware

If you still get warning messages then proceed to the next section titled "May 26, 2018 Update"

May 26, 2018 Update

Recently Intel has switched to download files called blobs which stands for Binary Large OBject (BLOB).

To see the new i915 driver installation methods see this answer updated today.

Skylake (skl) Firmware

There is a new link for accessing Skylake (skl) firmware for those with that graphics engine found here (01.org - Linux Graphics Firmware Downloads). A sample screen shot follows.

Intel Graphics for Linux 4

If you try to select the Kabylake (kbl) or Broxton (bxt) firmware you'll get an error message as these drivers have not been released to the public yet.

Missing Kabylake (kbl) and Broxton (bxt) Firmware

The old link requires special signon. Intel has changed their website link for the rest of us.

Questions still remain about the warning messages generated by sudo update-initramfs -u when Kernel version > 4.8 (Ubuntu 16.10 and Ubuntu 17.04):

W: Possible missing firmware /lib/firmware/i915/kbl_dmc_ver1_01.bin for module i915
W: Possible missing firmware /lib/firmware/i915/kbl_guc_ver9_14.bin for module i915
W: Possible missing firmware /lib/firmware/i915/bxt_guc_ver8_7.bin for module i915

At one time the bug report (bugs.launchpad.net - linux firmware bug) said the drivers simply do not exist and will not until a future chip called "kaby lake" is released. As of February 2017 however you can install these drivers following these instructions: Updated kernel to 4.8 now missing firmware warnings

Make the warning messages go away

As of February 2017 ignore this section and follow the instructions in the last paragraph above.

To make the warning message go away I did the following:

$ sudo cp assembly/hello  /lib/firmware/i915/kbl_dmc_ver1_01.bin
$ sudo cp assembly/hello /lib/firmware/i915/kbl_guc_ver9_14.bin
$ sudo cp assembly/hello /lib/firmware/i915/bxt_guc_ver8_7.bin
$ sudo update-initramfs -u
update-initramfs: Generating /boot/initrd.img-4.9.5-040905-generic

Voila! No more warning messages.

The program "hello" is a 504 byte assembler program that says "Hello World!". You can copy any small executable to the firmware binaries given in the error messages. When Intel eventually releases them the software updater will replace them with the real versions.

How to navigate Intel Graphics for Linux website

It was asked via comments how to navigate within the the new Intel website (01.org - Linux Graphics Downloads) which presents this screen:

Intel Graphics for Linux 1

Type Ubuntu 16.04 into the search field and click the Filter button.

For Ubuntu 16.10 select the first result. In our case Ubuntu 16.04 select the second result INTEL GRAPHICS UPDATE TOOL FOR LINUX* OS V2.0.2 and this screen appears:

Intel Graphics for Linux 2

In my case I selected Ubuntu 16.04 64-bit which downloaded the file intel-graphics-update-tool_2.0.2_amd64.deb to my ~/Downloads directory.

The next step is to open the terminal and use:

cd Downloads
sudo dpkg -i intel*.deb

NOTE: Intel uses the ancients ttf font and your installation will fail if it's not on your system. At this point you need to use:

sudo apt -f install
sudo apt update
sudo apt upgrade

Now you can run the Intel Graphics for Linux Updater tool as this screen shows:

Intel Graphics for Linux 3

Add Intel signatures for Ubuntu

During apt-get update you can see warning / error messages like this:

W: GPG error: https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 56A3DEF863961D39
E: The repository 'https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

You'll need to add Intel's signatures using:

wget --no-check-certificate https://download.01.org/gfx/RPM-GPG-KEY-ilg-4 -O - | \
sudo apt-key add -

Then update in Ubuntu:

sudo apt update
sudo apt upgrade

I also have faced a similar problem because I've updated the kernel from the Ubuntu Gnome 16.04 "Software" app (native package manager) and it crashed while updating.

So, I was barred to boot Ubuntu again because the linux-image was unsuccessfully generated.

To solve it from that point I did the following:

  1. Reboot linux and right after motherboard screen press Shift to enter into grub menu;
  2. Select your previous linux version from menu. In my case *4.4.0-21-generic and press Enter;
  3. Once Ubuntu is up again, uninstall the broken linux-image. In my case the *4.4.0-59-generic (I've used Synaptic package manager for it);
  4. Download and install the missing firmware from Intel page (same as Doug Smythies). In my case, I got the KabyLake kbl DMC - Ver 1.01;
  5. And finally, install again the linux kernel *4.4.0-59-generic (in my case) or just linux-generic for the latest complete generic Linux kernel.

Success! Kernel is up-to-date and all firmwares working fine!

Best regards!


If you are running debian (I have Debian GNU/Linux buster) just follow these steps:

  1. create the folder:

    sudo mkdir -p /lib/firmware/i915
  2. copy all files from https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/i915 to this folder

  3. Reconfigure the initramfs-tools package:

    sudo dpkg-reconfigure initramfs-tools
  • The command for Ubuntu is something like sudo update-initramfs -u but I'm on phone so can't confirm. Debian questions are off-topic here so your answer is unlikely to influence many people. – WinEunuuchs2Unix May 7 at 19:43

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