Update README To Document The Need To Mask The Getty Service On Raspbian Bookworm (#41)

* Updated README to reflect additional commands needed for Raspbian Bookworm

* Fixed typo in command

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Co-authored-by: faulty <faulty@evilcomputing.net>

README.md

@@ -174,12 +174,14 @@ Some extra notes for those who are using the Raspberry Pi, default Raspbian OS o
 
 1. Disable the Bluetooth services. Bluetooth will share the GPIO serial interface on `/dev/ttyAMA0`. On Rasbian OS or Debian OS, this is done by: `sudo systemctl disable bluetooth` then adding `dtoverlay=disable-bt` to `/boot/config.txt`.
 1. The default Rasbian OS and Debian OS will have a getty instance listening on `/dev/ttyAMA0`. This can conflict with the STM32, and is best if disabled. On Rasbian OS or Debian OS, this is done by: `systemctl disable serial-getty@ttyAMA0.service`
+1. On Debian Bookworm-based builds of Raspian OS, the getty instance on `/dev/ttyAMA0` gets rebuilt on boot via a systemd generator, even if you've already disabled it.  You'll need to disable this generator with: `sudo systemctl mask serial-getty@ttyAMA0.service`
 1. There's a default boot option which is also listening on the GPIO serial interface. This **must be disabled**. Open the `/boot/cmdline.txt` file in your favorite editor (vi or pico) and remove the `console=serial0,115200` part.
 
 The steps above can be done by the following commands:
 
 ```shell
 sudo systemctl disable bluetooth.service serial-getty@ttyAMA0.service
+sudo systemctl mask serial-getty@ttyAMA0.service
 grep '^dtoverlay=disable-bt' /boot/config.txt || echo 'dtoverlay=disable-bt' | sudo tee -a /boot/config.txt
 sudo sed -i 's/^console=serial0,115200 *//' /boot/cmdline.txt
 ```