diff --git a/support/dependencies/check-host-bison-flex.mk b/support/dependencies/check-host-bison-flex.mk
index 233b6c51cc..14a232fd44 100644
--- a/support/dependencies/check-host-bison-flex.mk
+++ b/support/dependencies/check-host-bison-flex.mk
@@ -1,5 +1,9 @@
 # If the system lacks bison or flex, add
 # dependencies to suitable host packages
+#
+# BR2_{BISON,FLES}_HOST_DEPENDENCY should only be used to build code
+# that runs on host, e.g. Kconfig. To build code for target use plain
+# host-{bison,flex}.
 
 ifeq ($(shell which bison 2>/dev/null),)
 BR2_BISON_HOST_DEPENDENCY = host-bison