diff --git a/src/arch/msp430fr5969lp/Makefile.inc b/src/arch/msp430fr5969lp/Makefile.inc
index f689b3fd1a918ecfbdfdc380f89443d13522389c..557fa90a4ed81a0ab394ddef0d3deca218837857 100644
--- a/src/arch/msp430fr5969lp/Makefile.inc
+++ b/src/arch/msp430fr5969lp/Makefile.inc
@@ -98,7 +98,8 @@ monitor:
 
 arch_help:
 	@echo "msp430fr5969lp specific flags:"
-	@echo "    cpu_freq = 16000000 (desired CPU frequency in Hz, not all values are supported)"
+	@echo "    cpu_freq = 16000000 (desired CPU frequency in Hz)"
+	@echo "        supported frequencies: 1 / 4 / 8 / 16 MHz"
 	@echo "    MSP430_FLASHER_DIR = /home/derf/var/projects/msp430/MSP430Flasher_1.3.7"
 	@echo "        (required for flashing, must contain libmsp430.so and MSP430Flasher)"
 
diff --git a/src/arch/msp430fr5994lp/Makefile.inc b/src/arch/msp430fr5994lp/Makefile.inc
index 6dcddf14aa1c652e38704e82f8410fd4527869b4..0c82dfc8a2f616e2975f08daaa037663743b8af8 100644
--- a/src/arch/msp430fr5994lp/Makefile.inc
+++ b/src/arch/msp430fr5994lp/Makefile.inc
@@ -102,7 +102,8 @@ monitor:
 
 arch_help:
 	@echo "msp430fr5994lp specific flags:"
-	@echo "    cpu_freq = 16000000 (desired CPU frequency in Hz, not all values are supported)"
+	@echo "    cpu_freq = 16000000 (desired CPU frequency in Hz)"
+	@echo "        supported frequencies: 1 / 4 / 8 / 16 MHz"
 	@echo "    MSP430_FLASHER_DIR = /home/derf/var/projects/msp430/MSP430Flasher_1.3.15"
 	@echo "        (required for flashing, must contain libmsp430.so and MSP430Flasher)"