diff --git a/deb.mk b/deb.mk
index 20b3b31f3..30f9e6d3a 100644
--- a/deb.mk
+++ b/deb.mk
@@ -92,8 +92,8 @@ deb-herokuish:
 	@echo "  sudo docker rmi gliderlabs/herokuish" >> /tmp/tmp/post-install
 	@echo "fi" >> /tmp/tmp/post-install
 	@echo "echo 'Importing herokuish into docker (around 5 minutes)'" >> /tmp/tmp/post-install
-	@echo 'if [[ ! -z $${http_proxy+x} ]]; then BUILDARGS="--build-args http_proxy=$$http_proxy"; fi' >> /tmp/tmp/post-install
-	@echo 'if [[ ! -z $${https_proxy+x} ]]; then BUILDARGS="$$BUILDARGS --build-args https_proxy=$$https_proxy"; fi' >> /tmp/tmp/post-install
+	@echo 'if [[ ! -z $${http_proxy+x} ]]; then BUILDARGS="--build-arg http_proxy=$$http_proxy"; fi' >> /tmp/tmp/post-install
+	@echo 'if [[ ! -z $${https_proxy+x} ]]; then BUILDARGS="$$BUILDARGS --build-arg https_proxy=$$https_proxy"; fi' >> /tmp/tmp/post-install
 	@echo 'if [[ ! -z $${BUILDARGS+x} ]]; then echo Adding proxy settings to docker build: $$BUILDARGS; fi' >> /tmp/tmp/post-install
 	@echo 'sudo docker build $$BUILDARGS -t gliderlabs/herokuish /var/lib/herokuish 1> /dev/null' >> /tmp/tmp/post-install