diff --git a/boards/ikea-tradfri/Makefile.features b/boards/ikea-tradfri/Makefile.features
index 904f1df7b9..1006ab232b 100644
--- a/boards/ikea-tradfri/Makefile.features
+++ b/boards/ikea-tradfri/Makefile.features
@@ -9,4 +9,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m4_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/sltb001a/Makefile.features b/boards/sltb001a/Makefile.features
index 6b5068bb24..eec9ddfd7d 100644
--- a/boards/sltb001a/Makefile.features
+++ b/boards/sltb001a/Makefile.features
@@ -11,4 +11,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m4_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/stk3600/Makefile.features b/boards/stk3600/Makefile.features
index 6872fee4e2..bff358e352 100644
--- a/boards/stk3600/Makefile.features
+++ b/boards/stk3600/Makefile.features
@@ -13,4 +13,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m3_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/stk3700/Makefile.features b/boards/stk3700/Makefile.features
index 6872fee4e2..bff358e352 100644
--- a/boards/stk3700/Makefile.features
+++ b/boards/stk3700/Makefile.features
@@ -13,4 +13,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m3_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features