Canonical has withdrawn the Intel Microcode update released on November 11 for all supported versions of Ubuntu Linux to fix a bug that causes boot failures on some Intel Tiger Lake systems.
On November 10, Intel released a new firmware for Intel Microcode on Linux systems. After the bugs were discovered, Canonical quickly fixed the Intel Microcode packages in all supported versions of Ubuntu, (Ubuntu 20.10, Ubuntu 20.04 LTS, Ubuntu 18.04 LTS, Ubuntu 16.04 LTS and Ubuntu 14.04 ESM), and released new versions of the kernel.
Unfortunately, the Intel Microcode update caused errors in some processors in the Intel Tiger Lake family, preventing the system from starting.
Therefore, Canonical again made the previous Intel Microcode update available only for the Tiger Lake family of processors.
The company informs them users that they can use the parameter dis_ucode_ldr of the kernel at menu boot to disable the loading of firmware for Intel Microcode in case modeof system recovery.
If you are using one of the supported versions of Ubuntu on a computer with an Intel Tiger Lake processor and have already installed yesterday's Intel Microcode update, it is recommended that you update the system again to new edition Intel Microcode that already exists in the main repository.
If you installed yesterday's Intel Microcode update and are experiencing a system boot failure, you should use the kernel command line command above to prevent the firmware from loading and recovering your system. Then update via the terminal with the following commands (they are two in one):
sudo apt update && sudo apt full-upgrade