diff --git a/README.md b/README.md
index 8ad36c7..e0465cc 100644
--- a/README.md
+++ b/README.md
@@ -48,3 +48,4 @@ An open source for samples is for example: https://philharmonia.co.uk/resources/
 # TODO
 * Connect USB stick with samples which should override the default samples
 * `ALSA lib pcm.c:8545:(snd_pcm_recover) underrun occurred`. Especially if using mp3s?
+* It's necessary to activate the serial via raspi-config, the configuration above does not activate it.