diff --git a/lib/definition-graal.js b/lib/definition-graal.js
index <HASH>..<HASH> 100644
--- a/lib/definition-graal.js
+++ b/lib/definition-graal.js
@@ -2,10 +2,13 @@ const Definition = require('./definition')
 
 module.exports = class GraalDefinition extends Definition {
   static Binary (definition) {
-    return ({ url, sha }) => ({
-      platform: this.platformFrom(url),
-      downloadUri: `${url}#${sha}`
-    })
+    return ({ url, sha }) =>
+      url.match(/\.tar\.gz$/)
+        ? {
+          platform: this.platformFrom(url),
+          downloadUri: `${url}#${sha}`
+        }
+        : null
   }
 
   static platformFrom (url) {
diff --git a/lib/definition.js b/lib/definition.js
index <HASH>..<HASH> 100644
--- a/lib/definition.js
+++ b/lib/definition.js
@@ -6,7 +6,9 @@ module.exports = class Definition {
       throw Error('no source or binaries')
     }
 
-    this.binaries = (this.binaries || []).map(this.constructor.Binary(this))
+    this.binaries = (this.binaries || [])
+      .map(this.constructor.Binary(this))
+      .filter(b => b)
   }
 
   get noSource () {
Skip assets that we don't support