Processor errata workarounds during UEFI BIOS initialization

How can one determine what specific instruction(s) or registers should be updated to implement specific errata workaround?

Once the BIOS has load the microcode, then next step is to implement specific errata workarounds. How a can the details of the workaround be understood, so that this can be implemented in the UEFI BIOS?

Here are details on specific issue:

- "How to determine cause of processor frequency scale down to ~200 MHz due to ThermStatus": https://software.intel.com/en-us/forums/software-tuning-performance-optimization-platform-monitoring/topic/815194

- "How to determine if errata workarounds are implemented in a UEFI BIOS": https://software.intel.com/en-us/forums/software-tuning-performance-optimization-platform-monitoring/topic/816700

- "Does Intel manufacture older generations of (4th gen) Intel Core processors?": https://forums.intel.com/s/question/0D50P00004R3629SAB/does-intel-manufacture-older-generations-of-4th-gen-intel-core-processors?language=en_US