diff --git a/Makefile b/Makefile
index 8877682cd..21f3946bb 100644
--- a/Makefile
+++ b/Makefile
@@ -153,16 +153,6 @@ ifeq ($(USE_LIBBACKTRACE), 0)
   NIM_PARAMS += -d:disable_libbacktrace
 endif
 
-# TODO: port this back to nimbus-build-system
-# after we can switch to nim 1.6.16
-# This rule override the one in targets.mk
-libnatpmp.a: | sanity-checks
-ifeq ($(OS), Windows_NT)
-	+ "$(MAKE)" -C vendor/nim-nat-traversal/vendor/libnatpmp-upstream OS=mingw CC=$(CC) CFLAGS="-Wall -Wno-cpp -Os -DWIN32 -DNATPMP_STATICLIB -DENABLE_STRNATPMPERR -DNATPMP_MAX_RETRIES=4 $(CFLAGS)" $@ $(HANDLE_OUTPUT)
-else
-	+ "$(MAKE)" CFLAGS="-Wall -Wno-cpp -Os -DENABLE_STRNATPMPERR -DNATPMP_MAX_RETRIES=4 $(CFLAGS)" -C vendor/nim-nat-traversal/vendor/libnatpmp-upstream $@ $(HANDLE_OUTPUT)
-endif
-
 deps: | deps-common nat-libs nimbus.nims
 ifneq ($(USE_LIBBACKTRACE), 0)
 deps: | libbacktrace
diff --git a/vendor/nimbus-build-system b/vendor/nimbus-build-system
index 2e6950547..fc18925ce 160000
--- a/vendor/nimbus-build-system
+++ b/vendor/nimbus-build-system
@@ -1 +1 @@
-Subproject commit 2e695054798f27db147bb1b89962290d8cbb16c2
+Subproject commit fc18925ce12ceb9c088db8f8eac1bd39b2225585