System Extensions in Big Sur

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

If your radio has an internal sound card, make sure that is supported as well.

If you are unsure - install Big Sur on an external HD so that you can fall back if you have to.

Posted:  March 21, 2020, Updated: August 8, 2021

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 with built-in support for many (but not all) serial devices.

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

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

Manufacturer supplied drivers:

Workaround for legacy kext drivers:

To check SIP status from the macOS Terminal enter...
$ csrutil status