The Case for an FCC Software Update
https://www.satcom.guru/2018/11/737-...n-command.html
...FCC Pitch Axis augmentation (Mach Trim, Speed Trim, and MCAS) commands may be based on a single sensor input. These commands should be checked against a calculation based on a second sensor set before becoming valid. A software update to the FCC may provide support for a dual channel mandate.