Fingeprint script: better instructions

selfdrive/debug/get_fingerprint.py

@@ -6,8 +6,10 @@
 # - connect to a Panda
 # - run selfdrive/boardd/boardd
 # - launching this script
-# - since some messages are published at low frequency, keep this script running for few
-#   seconds, until all messages are received at least once
+# - turn on the car in STOCK MODE (set giraffe switches properly).
+#   Note: it's very important that the car is in stock mode, in order to collect a complete fingerprint
+# - since some messages are published at low frequency, keep this script running for at least 30s,
+#   until all messages are received at least once
 
 import zmq
 import selfdrive.messaging as messaging