diff --git a/Makefile b/Makefile
index 64cb92e..9c67308 100644
--- a/Makefile
+++ b/Makefile
@@ -76,12 +76,12 @@ typecheck: ## mypy over the gateway sources
 
 .PHONY: build-firmware
 build-firmware: ## Build the ESP-IDF firmware (sources export.sh for you)
-	@test -f $(IDF_EXPORT) || { echo "FAIL — no ESP-IDF at $(IDF_EXPORT); set IDF_EXPORT=<path>/export.sh"; exit 1; }
+	@test -f $(IDF_EXPORT) || { echo "FAIL — no ESP-IDF at $(IDF_EXPORT); set IDF_EXPORT=<path>/export.sh"; exit 69; }
 	. $(IDF_EXPORT) && cd firmware && idf.py build
 
 .PHONY: flash
 flash: ## Flash and monitor the device (PORT=/dev/ttyACM0 by default)
-	@test -f $(IDF_EXPORT) || { echo "FAIL — no ESP-IDF at $(IDF_EXPORT); set IDF_EXPORT=<path>/export.sh"; exit 1; }
+	@test -f $(IDF_EXPORT) || { echo "FAIL — no ESP-IDF at $(IDF_EXPORT); set IDF_EXPORT=<path>/export.sh"; exit 69; }
 	. $(IDF_EXPORT) && cd firmware && idf.py -p $(or $(PORT),/dev/ttyACM0) flash monitor
 
 # --- sim ----------------------------------------------------------------------