1 files changed, 1 insertions, 1 deletions
diff --git a/Sam.mk b/Sam.mk
index cc588a1..2e19730 100644
--- a/Sam.mk
+++ b/Sam.mk
@@ -38,7 +38,7 @@ ifneq ($(TEST),)
     ALTERNATE_CORE_PATH = $(DEPENDENCIES_DIR)/samd
     CMSIS_DIR = $(DEPENDENCIES_DIR)/CMSIS/CMSIS
     CMSIS_ATMEL_DIR = $(DEPENDENCIES_DIR)/CMSIS-Atmel/CMSIS
-    ARM_TOOLS_DIR = $(basename $(basename $(firstword $(wildcard $(DEPENDENCIES_DIR)/gcc-arm-none-eabi*))))
+    ARM_TOOLS_DIR := $(basename $(basename $(firstword $(wildcard $(DEPENDENCIES_DIR)/gcc-arm-none-eabi*))))
 endif
 
 ifndef ARDUINO_PACKAGE_DIR