diff --git a/packages/metro-cache/src/stableHash.js b/packages/metro-cache/src/stableHash.js
index 133c3755..040e5b91 100644
--- a/packages/metro-cache/src/stableHash.js
+++ b/packages/metro-cache/src/stableHash.js
@@ -32,7 +32,7 @@ function stableHash(value: mixed) {
   return crypto
     .createHash('md4')
     .update(JSON.stringify(value, canonicalize))
-    .digest();
+    .digest('buffer');
 }
 
 module.exports = stableHash;
diff --git a/packages/metro/src/shared/output/meta.js b/packages/metro/src/shared/output/meta.js
index e761ecaf..bee3cbcd 100644
--- a/packages/metro/src/shared/output/meta.js
+++ b/packages/metro/src/shared/output/meta.js
@@ -31,7 +31,7 @@ module.exports = function(
   const buffer: Buffer = asBuffer(code, encoding);
   const hash = crypto.createHash('sha1');
   hash.update(buffer);
-  const digest = hash.digest();
+  const digest = hash.digest('buffer');
   const signature = Buffer.alloc
     ? Buffer.alloc(digest.length + 1)
     : new Buffer(digest.length + 1);