[Ubuntu 18.04] Prevent kernel from being updated with apt update

--Use the apt-mark hold command. Put the following packages in hold. - linux-generic-hwe-18.04 hold - linux-headers-5.4.0-42-generic hold - linux-headers-generic-hwe-18.04 hold - linux-hwe-5.4-headers-5.4.0-42 hold - linux-image-5.4.0-42-generic hold - linux-image-generic-hwe-18.04 hold - linux-modules-5.4.0-42-generic hold - linux-modules-extra-5.4.0-42-generic hold

$ sudo apt-mark hold linux-generic-hwe-18.04 linux-headers-5.4.0-42-generic linux-headers-generic-hwe-18.04 linux-hwe-5.4-headers-5.4.0-42 linux-image-5.4.0-42-generic linux-image-generic-hwe-18.04 linux-modules-5.4.0-42-generic linux-modules-extra-5.4.0-42-generic

• Confirmation

$ dpkg --get-selections | grep hold

--To release the hold, use the apt-mark unhold command.

$ sudo apt-mark unhold linux-generic-hwe-18.04 linux-headers-5.4.0-42-generic linux-headers-generic-hwe-18.04 linux-hwe-5.4-headers-5.4.0-42 linux-image-5.4.0-42-generic linux-image-generic-hwe-18.04 linux-modules-5.4.0-42-generic linux-modules-extra-5.4.0-42-generic