System Extensions in Big Sur
Summary: Don't install Big Sur until
you make sure your USB/Serial connection will work!
your radio has an internal sound card, make sure that is
supported as well.
are unsure - install Big Sur on an external HD so that you can
fall back if you have to.
Posted: March 21, 2020,
Updated: March 16, 2021
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.
intends to eventually prohibit kernel extensions for security
reasons and replace the functionality with DriverKit extensions
running in user space.
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.
DXP is a Standard USB Class device and does not require
a 3rd party driver on Intel or Apple M1 Silicon Macs.
released Big Sur with built-in support for many (but not all)
Big Sur DriverKit (Intel and M1) currently supports
the following devices without any 3rd party driver:
Most devices tested so far with standard VID/PID including...
- K9JM CI-V Router
- Generic UART cables
- dext in development.
- CP2102 (Icom IC-7610, IC-7300,
IC-9700, TS-590 etc.)
Most devices tested so far.
Big Sur DriverKit does not
currently support the following devices without a
3rd party driver:
- CP2105 (Yaesu
FT-991, FTdx101, etc.)
- Disable SIP (not usually
recommended - proceed with caution)
- Shutdown Mac
- Hold <command> R during startup
until Apple Logo.
- Run Terminal from Utilities menu in
Recovery mode and enter the following...
(don't enter the $ prompt, press return at the end of
- $ csrutil disable
- $ reboot
- Install SiLabs driver in macOS.
To check SIP
status from the macOS Terminal enter...
$ csrutil status
- Use an FTDI based UART cable with
the Radio's back panel RS-232 DB-9 serial CAT port.
- Safer option, works on Apple M1 Silicon.
- Most Yaesu DB-9 connections require a straight-thru
rather than a null modem cable.
- Even though the USB UART is not yet supported, the USB
Audio CODEC is available in Big Sur.
- Make sure port is set for RS232C not Tuner.
- Silicon Labs has released a new
released December 23, 2020
- YMMV: Installs but doesn't load on Apple M1 Silicon
- Installs and loads on Intel macOS 11.3b3