diff --git a/Makefile.builder b/Makefile.builder
index 7ad9df1..b41efd6 100644
--- a/Makefile.builder
+++ b/Makefile.builder
@@ -1,8 +1,8 @@
 MIRAGE_KERNEL_NAME = qubes_firewall.xen
-#SOURCE_BUILD_DEP := ssh-agent-build-dep
-OCAML_VERSION ?= 4.05.0
+SOURCE_BUILD_DEP := mfw-build-dep
+OCAML_VERSION ?= 4.07.1
 
-#ssh-agent-build-dep:
-#	opam pin -y add angstrom https://github.com/reynir/angstrom.git#no-c-blit
+mfw-build-dep:
+  opam pin -y add mirage 3.4.0
 #	opam pin -y add ssh-agent https://github.com/reynir/ocaml-ssh-agent.git