diff --git a/controllers/nginx/Makefile b/controllers/nginx/Makefile
index dd6944501..c5e027a2b 100644
--- a/controllers/nginx/Makefile
+++ b/controllers/nginx/Makefile
@@ -54,7 +54,9 @@ endif
 #        QEMUARCH=s390x
 #endif
 
-TEMP_DIR ?= $(shell mktemp -d)
+export TEMP_DIR ?= $(shell mktemp -d)
+
+DOCKERFILE := $(TEMP_DIR)/rootfs/Dockerfile
 
 all: all-container
 
@@ -71,19 +73,19 @@ all-push: $(addprefix sub-push-,$(ALL_ARCH))
 container: .container-$(ARCH)
 .container-$(ARCH):
 	cp -r ./* $(TEMP_DIR)
-	cd $(TEMP_DIR) && $(SED_I) 's|BASEIMAGE|$(BASEIMAGE)|g' rootfs/Dockerfile
-	cd $(TEMP_DIR) && $(SED_I) "s|QEMUARCH|$(QEMUARCH)|g" rootfs/Dockerfile
-	cd $(TEMP_DIR) && $(SED_I) "s|DUMB_ARCH|$(DUMB_ARCH)|g" rootfs/Dockerfile
+	$(SED_I) 's|BASEIMAGE|$(BASEIMAGE)|g' $(DOCKERFILE)
+	$(SED_I) "s|QEMUARCH|$(QEMUARCH)|g" $(DOCKERFILE)
+	$(SED_I) "s|DUMB_ARCH|$(DUMB_ARCH)|g" $(DOCKERFILE)
 
 ifeq ($(ARCH),amd64)
 	# When building "normally" for amd64, remove the whole line, it has no part in the amd64 image
-	cd $(TEMP_DIR) && $(SED_I) "/CROSS_BUILD_/d" rootfs/Dockerfile
+	$(SED_I) "/CROSS_BUILD_/d" $(DOCKERFILE)
 else
 	# When cross-building, only the placeholder "CROSS_BUILD_" should be removed
 	# Register /usr/bin/qemu-ARCH-static as the handler for ARM binaries in the kernel
 	$(DOCKER) run --rm --privileged multiarch/qemu-user-static:register --reset
 	curl -sSL https://github.com/multiarch/qemu-user-static/releases/download/$(QEMUVERSION)/x86_64_qemu-$(QEMUARCH)-static.tar.gz | tar -xz -C $(TEMP_DIR)/rootfs
-	cd $(TEMP_DIR) && $(SED_I) "s/CROSS_BUILD_//g" rootfs/Dockerfile
+	$(SED_I) "s/CROSS_BUILD_//g" $(DOCKERFILE)
 endif
 
 	$(DOCKER) build -t $(MULTI_ARCH_IMG):$(TAG) $(TEMP_DIR)/rootfs