Network not working after downgrading kernel
I'm currently using Ubuntu 18.04.1, with kernel version 5.3.0-40.
I need to downgrade to kernel 4.15.x to use my work VPN application.
I downloaded the older kernel version and booted into it, but then I have no connection in there (neither with LAN or with wi-fi). I guess it's a driver problem, but since I'm a newbie to the world of Linux I really don't know what to do even after searching online for a bit.
Any help would be really appreciated, thank you.
Edit:
apt list --installed | grep ^linux output
dmesg output `
lspci output
lsusb output
I had a similar problem where my cellular modem was not being recognized after downgrading my Ubuntu Linux kernel.
To solve my problem, I had to ensure the following modules-extra package was also installed:
linux-modules-extra-5.4.0-42-generic
I had previously only installed the following:
sudo apt-get -y install \
linux-image-5.4.0-42-generic \
linux-headers-5.4.0-42-generic \
linux-modules-5.4.0-42-generic
The following command is helpful for checking which packages are installed:
dpkg -l | grep "linux-"
ii binutils-x86-64-linux-gnu 2.34-6ubuntu1.1 amd64 GNU binary utilities, for x86-64-linux-gnu target
ii linux-base 4.5ubuntu3.5 all Linux image base package
ii linux-firmware 1.187.15 all Firmware for Linux kernel drivers
ii linux-generic-hwe-20.04 5.8.0.59.66~20.04.42 amd64 Complete Generic Linux kernel and headers
ii linux-headers-5.4.0-42 5.4.0-42.46 all Header files related to Linux kernel version 5.4.0
ii linux-headers-5.4.0-42-generic 5.4.0-42.46 amd64 Linux kernel headers for version 5.4.0 on 64 bit x86 SMP
ii linux-headers-5.8.0-43-generic 5.8.0-43.49~20.04.1 amd64 Linux kernel headers for version 5.8.0 on 64 bit x86 SMP
ii linux-headers-5.8.0-59-generic 5.8.0-59.66~20.04.1 amd64 Linux kernel headers for version 5.8.0 on 64 bit x86 SMP
ii linux-headers-generic-hwe-20.04 5.8.0.59.66~20.04.42 amd64 Generic Linux kernel headers
ii linux-hwe-5.8-headers-5.8.0-43 5.8.0-43.49~20.04.1 all Header files related to Linux kernel version 5.8.0
ii linux-hwe-5.8-headers-5.8.0-59 5.8.0-59.66~20.04.1 all Header files related to Linux kernel version 5.8.0
ii linux-image-5.4.0-42-generic 5.4.0-42.46 amd64 Signed kernel image generic
ii linux-image-5.8.0-43-generic 5.8.0-43.49~20.04.1 amd64 Signed kernel image generic
ii linux-image-5.8.0-59-generic 5.8.0-59.66~20.04.1 amd64 Signed kernel image generic
ii linux-image-generic-hwe-20.04 5.8.0.59.66~20.04.42 amd64 Generic Linux kernel image
ii linux-libc-dev:amd64 5.4.0-77.86 amd64 Linux Kernel Headers for development
ii linux-modules-5.4.0-42-generic 5.4.0-42.46 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-5.8.0-43-generic 5.8.0-43.49~20.04.1 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-5.8.0-59-generic 5.8.0-59.66~20.04.1 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-extra-5.4.0-42-generic 5.4.0-42.46 amd64 Linux kernel extra modules for version 5.4.0 on 64 bit x86 SMP
ii linux-modules-extra-5.8.0-43-generic 5.8.0-43.49~20.04.1 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-modules-extra-5.8.0-59-generic 5.8.0-59.66~20.04.1 amd64 Linux kernel extra modules for version 5.8.0 on 64 bit x86 SMP
ii linux-sound-base 1.0.25+dfsg-0ubuntu5 all base package for ALSA and OSS sound systems