diff --git a/makefiles/docker.inc.mk b/makefiles/docker.inc.mk
index 2e4e61f32f..424192916e 100644
--- a/makefiles/docker.inc.mk
+++ b/makefiles/docker.inc.mk
@@ -52,6 +52,7 @@ export DOCKER_ENV_VARS += \
   LTO \
   OBJCOPY \
   OFLAGS \
+  PARTICLE_MONOFIRMWARE \
   PREFIX \
   QUIET \
   WERROR \