diff --git a/.github/workflows/osx.yml b/.github/workflows/osx.yml
index 5aeceea..ba4395e 100644
--- a/.github/workflows/osx.yml
+++ b/.github/workflows/osx.yml
@@ -35,7 +35,7 @@ jobs:
           brew install automake autoconf
           curl -L https://raw.githubusercontent.com/roswell/roswell/master/scripts/install-for-ci.sh | sh
           ros install snmsts/sn.github roswell/sbcl_bin
-          make zstd
+          make -f Build  zstd
           bash -c "cd zstd/lib; sudo make PREFIX=/usr/local install-includes install-static clean"
           rm -f /usr/local/lib/libzstd*.dylib /opt/homebrew/lib/libzstd*.dylib
       - name: build & upload
diff --git a/Build b/Build
index 139db71..5a66ca9 100644
--- a/Build
+++ b/Build
@@ -9,6 +9,10 @@ SBCL_OPTIONS ?=--with-sb-core-compression
 LISP_IMPL ?= ros -L sbcl-bin without-roswell=t --no-rc run
 MAKEFILE_JUSTNAME := $(firstword $(MAKEFILE_LIST))
 DOCKER_REPO ?= docker.pkg.github.com/roswell/sbcl_bin
+ZSTD_BRANCH ?= v1.5.6
+
+zstd:
+	git clone --depth 5 https://github.com/facebook/zstd --branch=$(ZSTD_BRANCH)
 
 compile: show
 	@[ -n "$(VERSION)" ] || (echo version should be set; false)