diff --git a/circuit-python-lora-passthrough/boot.py b/circuit-python-lora-passthrough/boot.py
index 609f9096..8b54a07d 100644
--- a/circuit-python-lora-passthrough/boot.py
+++ b/circuit-python-lora-passthrough/boot.py
@@ -1,7 +1,10 @@
 """
 boot.py
 
-TODO(nateinaction): I don't know what this file is for yet.
+This file helps to use an RP2350 CircuitPython environment as a passthrough for
+interacting with the radio and F Prime GDS. The usb_cdc.enable() function creates a
+USB serial endpoint that the GDS can connect to to receive all the data that is
+streamed out. The function has to be called in boot.py before the USB device is enabled.
 """
 
 import usb_cdc