loader: add script to de-register ftdi_sio

alchitry-loader/Makefile

@@ -1,8 +1,16 @@
 export DOCKER_BUILDKIT=1
 
+.PHONY: loader
 loader:  ## build the loader in docker (linux)
 	docker build -o . .
 
+.PHONY: ftdi-unbind
+ftdi-unbind:  ## unbind the ftdi-sio devices on linux (uses sudo)
+	sh -c "cd /sys/bus/usb/drivers/ftdi_sio && \
+	for dev in *:*; do \
+		echo \$$dev | sudo tee unbind ; \
+	done"
+
 .PHONY: clean
 clean:
 	rm -rf loader $(objects)

alchitry-loader/README.md

@@ -28,6 +28,17 @@ Test it out
 
 `./alchitry_loader`
 
+
+## Linux and macOS and libftd2xx
+
+On Linux (and macOS?) the default kernel drivers prevent libftd2xx from working properly.
+On Linux, you can use this to de-register all ftdi-sio devices (until plugged again):
+
+```
+make ftdi-unbind
+```
+
+
 ## Usage
 
 ```