I have installed Ubuntu alongside Windows 8.1. But the wifi is not working in Ubuntu (perhaps the drivers are not present), which worked fine in windows. Also I cant connect with Ethernet since my laptop does not have an Ethernet port. So is there any way for me to connect to the internet in ubuntu?
Edit: Output of the terminal command lspci -knn | grep Net -A2:

vikram@vikram-Inspiron-11-3148:~$ lspci -knn | grep Net -A2
01:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)
    Subsystem: Dell Device [1028:0018]
    Kernel driver in use: bcma-pci-bridge

I did what Pilot6 suggested. Here is the output:

vikram@vikram-Inspiron-11-3148:~$ sudo dpkg -i *.deb
[sudo] password for vikram: 
Selecting previously unselected package bcmwl-kernel-source.
(Reading database ... 163804 files and directories currently installed.)
Preparing to unpack bcmwl-kernel-source_6.30.223.141+bdcom-0ubuntu2_amd64.deb ...
Unpacking bcmwl-kernel-source ( ...
Selecting previously unselected package dkms.
Preparing to unpack dkms_2.2.0.3-1.1ubuntu5.14.04_all.deb ...
Unpacking dkms ( ...
Setting up dkms ( ...
Setting up bcmwl-kernel-source ( ...
Loading new bcmwl- DKMS files...
First Installation: checking all kernels...
Building only for 3.16.0-30-generic
Building for architecture x86_64
Building initial module for 3.16.0-30-generic
ERROR (dkms apport): kernel package linux-headers-3.16.0-30-generic is not supported
Error! Bad return status for module build on kernel: 3.16.0-30-generic (x86_64)
Consult /var/lib/dkms/bcmwl/ for more information.
modprobe: FATAL: Module wl not found.
update-initramfs: deferring update (trigger activated)
Processing triggers for man-db ( ...
Processing triggers for initramfs-tools (0.103ubuntu4.2) ...
update-initramfs: Generating /boot/initrd.img-3.16.0-30-generic
  • What about using a USB modem? – Sharad Gautam May 21 '15 at 16:58
  • 1
    Please edit your question and add output of "lspci -knn | grep Net -A2" terminal command. – Pilot6 May 21 '15 at 16:59
  • @ln78 Please Edit Your title and add more info. – Sharad Gautam May 21 '15 at 17:02
  • I updated the answer. They install new kernel, but old driver. – Pilot6 May 21 '15 at 18:01
  • Possible duplicate of Installing "fimware-b43-installer" offline – Woeitg Feb 10 '16 at 10:26

You need to install wireless driver.

Insert your Ubuntu installation disk or a flash drive and copy these files from the installation disk to your Home directory:


Then run the following in terminal:

sudo dpkg -i *.deb

If you have UEFI BIOS, you need to disable Secure Boot to load the driver.

18.04 update:

The solution won't work on 18.04, because build-essential and its dependencies are not installed by default. The dpkg command will complain that dependencies are not installed.

You can manually find the required packages on the installation media ("pool" directory sorted by alphabet) and install them the same way as the dkms package. I hope nothing is missing there.

  • The second link is not working,can you please look into it and give an alternate place to download – SpringLearner Oct 25 '15 at 5:37
  • I updated the link. But it will be changed from time to time. – Pilot6 Oct 25 '15 at 10:00
  • I have just used this advice for Xubuntu 16.04 and installing the driver was no problem. I guess they have fixed the problem from 14.04.2. – Martin - マーチン Jul 28 '16 at 14:13
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    I have dowloaded both the Standard and Alternate installers. Don't see them. Only main and universe folders under pool. No restricted. No dkms in d folder. I see djvulibre and dmidecode. – sureshvv Jul 13 '18 at 22:24
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    askubuntu.com/questions/730799/… worked best – sureshvv Jul 14 '18 at 5:53

I recently needed to install the Wifi firmware for an older repurposed iMac 9,1. It had Broadcom 4322 Wifi, and Nvidia Ethernet, neither worked with 20.04. It found the card and tried the correct module (b43) but complained via dmesg "firmware not found."

The following steps I found online worked:

  • Find the broadcom firmware on another machine:

  • Install ./pool/main/b43-fwcutter*.deb manually from Ubuntu Disc/Flash drive.

  • Run the following:

    • sudo b43-fwcutter -w /lib/firmware broadcom-wl-*.o # write to /lib
    • sync
    • sudo modprobe -r b43 # remove
    • sudo modprobe b43 # reload

With that Network manager noticed and started up Wifi. :-D

To automate the firmware update, this can be done now that the network is up:

  • Enable multiverse in software-properties-gtk or apt/sources
  • sudo apt-get install firmware-b43-installer

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