Since the microcode is stored and automatically loaded by the BIOS/UEFI, motherboard manufacturers required to issue an update. However, manufacturers normally release firmware updates only for their newest products. Plenty of motherboards still remain vulnerable until this very day.
Intel Microcode Boot Loader is a workaround for the microcode problem on Intel-based motherboards. It updates the microcode every time the system is booted. Based on Intel BIOS Implementation Test Suite (BITS), users no longer need to modify BIOS/UEFI ROMs to stay protected from security vulnerabilities, bugs and erratas.
This solution requires permanently plugged USB flash drive with at least 25MB (or similar device) and BIOS/UEFI supporting boot from USB devices. Alternatively, advanced users can install it to a local drive on top of the System Reserved partition (see localdrive.txt for instructions).