diff --git a/pkg/semtech-loramac/doc.txt b/pkg/semtech-loramac/doc.txt
index dcac5e29e1a9ead043749f730ec497beff4c3ecd..074cc74496d61c3a2d496673c649356ad2f92643 100644
--- a/pkg/semtech-loramac/doc.txt
+++ b/pkg/semtech-loramac/doc.txt
@@ -32,6 +32,7 @@
  * set at compile time. Example for EU868:
  * ```
  *     CFLAGS += -DREGION_EU868
+ *     CFLAGS += -DLORAMAC_ACTIVE_REGION=LORAMAC_REGION_EU868
  * ```
  *
  * # Using the package API