diff --git a/makefiles/boot/riotboot.mk b/makefiles/boot/riotboot.mk
index 7e1dd1a99a..c436ae4392 100644
--- a/makefiles/boot/riotboot.mk
+++ b/makefiles/boot/riotboot.mk
@@ -59,7 +59,7 @@ $(HEADER_TOOL): FORCE
 	@echo "compiling $@..."
 	$(Q)/usr/bin/env -i \
 		QUIET=$(QUIET) \
-		PATH=$(PATH) \
+		PATH="$(PATH)" \
 			$(MAKE) --no-print-directory -C $(HEADER_TOOL_DIR) all
 
 # Generate RIOT header and keep the original binary file
@@ -78,7 +78,7 @@ riotboot: $(SLOT_RIOT_BINS)
 riotboot/flash-bootloader: riotboot/bootloader/flash
 riotboot/bootloader/%:
 	$(Q)/usr/bin/env -i \
-		QUIET=$(QUIET) PATH=$(PATH)\
+		QUIET=$(QUIET) PATH="$(PATH)"\
 		EXTERNAL_BOARD_DIRS="$(EXTERNAL_BOARD_DIRS)" BOARD=$(BOARD)\
 		DEBUG_ADAPTER_ID=$(DEBUG_ADAPTER_ID)\
 			$(MAKE) --no-print-directory -C $(RIOTBOOT_DIR) $*