Most of the time the BIOS upgrades are only pushed to allow for urgent issues such as security flaws or holes rather than adding new features.
The issues with supporting new hardware in older platforms is not within BIOS to fix. The hardware itself may not be compatible and would require a new system board to allow for new hardware to be properly attached.
I do not work for Lenovo, I only provide suggestions based on my personal willingness to help others. All advice and comments are based on my experience, and do not reflect Lenovo policy, terms or conditions.