System Extensions in Big Sur and Monterey

Summary: Don't install Big Sur or Monterey until you make sure your USB/Serial connection will work!

Most of the UART manufacturers have released new drivers that are compatible with Big Sur and Monterey (see below).

Due to a change in Monterey, port symlinks may not be available on some Macs (use /dev/cu. port name instead).

Posted:  March 21, 2020, Updated: November 21, 2021


Background: Warnings for Legacy System Extensions started to appear on reboot after installing macOS 10.15.4

These extensions are provided by the manufacturers (FTDI, Silicon Labs etc.) of internal and external USB/Serial adapters (UARTS) and are needed for CAT control of many serial port (non-LAN) based radios, rotor controllers, etc.

Apple intends to eventually prohibit kernel extensions for security reasons and replace the functionality with DriverKit extensions running in user space.

The UART manufacturers have announced their intention to support Apple's migration from Kernel Extensions to DriverKit Extensions.

Many UARTs are already supported automatically by Apple supplied Driver Kit extensions in Big Sur.

As Apple System Extensions and DriverKit adds functionality, 3rd party kernel extensions with matching functionality will not be needed and will not load.

microHAM DXP is a Standard USB Class device and does not require a 3rd party driver on Intel or Apple M1 Silicon Macs.


Native DriverKit Support:

Apple released Big Sur and Monterey with built-in support for many (but not all) serial devices.

Big Sur/Monterey DriverKit (Intel and M1) currently supports the following devices without any 3rd party driver:

Big Sur/Monterey
DriverKit does not currently support the following devices without a 3rd party driver:

Manufacturer supplied drivers: