diff --git a/boards/common/frdm/Makefile.include b/boards/common/frdm/Makefile.include
index d57d9dc6b9..7769a8e6ed 100644
--- a/boards/common/frdm/Makefile.include
+++ b/boards/common/frdm/Makefile.include
@@ -8,6 +8,9 @@ DEBUG_ADAPTER ?= dap
 #DEBUG_ADAPTER ?= jlink
 
 # Configuration for OpenOCD v0.10.0 and newer
+# For KW41Z, an OpenOCD version built from source is required. The support for
+# kw41z was introduced in
+# https://github.com/ntfreak/openocd/2c8602ed9f084d6680cec7d0ca1d5dc71c865a5f
 export OPENOCD_CONFIG ?= $(RIOTBOARD)/common/frdm/dist/openocd-$(CPU_FAMILY).cfg
 
 # Check the flash configuration field before flashing