diff --git a/packages/gatsby-source-filesystem/src/create-file-node.js b/packages/gatsby-source-filesystem/src/create-file-node.js
index e64e86d53fa90..3084876a6f602 100644
--- a/packages/gatsby-source-filesystem/src/create-file-node.js
+++ b/packages/gatsby-source-filesystem/src/create-file-node.js
@@ -44,7 +44,7 @@ exports.createFileNode = async (
     internal = {
       contentDigest,
       type: `File`,
-      mediaType: mediaType ? mediaType : `application/octet-stream`,
+      mediaType,
       description: `File "${path.relative(process.cwd(), slashed)}"`,
     }
   }
diff --git a/packages/gatsby-transformer-toml/src/gatsby-node.js b/packages/gatsby-transformer-toml/src/gatsby-node.js
index 8cb73188590d9..f4caa0f627769 100644
--- a/packages/gatsby-transformer-toml/src/gatsby-node.js
+++ b/packages/gatsby-transformer-toml/src/gatsby-node.js
@@ -5,7 +5,7 @@ const crypto = require(`crypto`)
 async function onCreateNode({ node, actions, loadNodeContent, createNodeId }) {
   const { createNode, createParentChildLink } = actions
   // Filter out non-toml content
-  // Currently TOML files are considered 'application/octet-stream' in 'mime-db'
+  // Currently TOML files are considered null in 'mime-db'
   // Hence the extension test instead of mediaType test
   if (node.extension !== `toml`) {
     return
diff --git a/packages/gatsby/src/schema/types/type-file.js b/packages/gatsby/src/schema/types/type-file.js
index 9f672a65ebe1c..301db11b6fce5 100644
--- a/packages/gatsby/src/schema/types/type-file.js
+++ b/packages/gatsby/src/schema/types/type-file.js
@@ -28,7 +28,7 @@ export function setFileNodeRootType(fileNodeRootType) {
 function pointsToFile(nodes, key, value) {
   const looksLikeFile =
     _.isString(value) &&
-    mime.getType(value) !== `application/octet-stream` &&
+    mime.getType(value) !== null &&
     // domains ending with .com
     mime.getType(value) !== `application/x-msdownload` &&
     isRelative(value) &&