Ubuntu Security Notice 4385-2 - USN-4385-1 provided updated Intel Processor Microcode. Unfortunately, that update prevented certain processors in the Intel Skylake family from booting successfully. Additionally, on Ubuntu 20.04 LTS, late loading of microcode was enabled, which could lead to system instability. This update reverts the microcode update for the Skylake processor family and disables the late loading option on Ubuntu 20.04 LTS. Please note that the 'dis_ucode_ldr' kernel command line option can be added in the boot menu to disable microcode loading for system recovery. Various other issues were also addressed.
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