diff --git a/build.sh b/build.sh
index d0428b40..7554e7da 100755
--- a/build.sh
+++ b/build.sh
@@ -9,6 +9,7 @@ CRATE=$1
 BUILDCMD=${BUILDCMD:-"dpkg-buildpackage -b -uc -us"}
 
 mkdir -p build
+echo system >build/rust-toolchain
 rm -rf "build/${CRATE}"
 
 debcargo package --config "$PWD/${CRATE}/debian/debcargo.toml" --changelog-ready --no-overlay-write-back --directory "$PWD/build/${CRATE}" "${CRATE}" "$(dpkg-parsechangelog -l "${CRATE}/debian/changelog" -SVersion | sed -e 's/-.*//')"