--- a/mobile/android/base/java/org/mozilla/gecko/dlc/DownloadAction.java
+++ b/mobile/android/base/java/org/mozilla/gecko/dlc/DownloadAction.java
@@ -232,16 +232,20 @@ public class DownloadAction extends Base
             // a reference to that stream we wouldn't be able to close it if GZInputStream throws.
             // (The BufferedInputStream constructor doesn't throw, so we don't need to care about it.)
             inputStream = new BufferedInputStream(new FileInputStream(sourceFile));
             gzInputStream = new GZIPInputStream(inputStream);
             outputStream = new BufferedOutputStream(new FileOutputStream(temporaryFile));
 
             IOUtils.copy(gzInputStream, outputStream);
 
+            // We need to flush the output stream here so that everything is written before we verify
+            // the checksum of the file.
+            outputStream.flush();
+
             if (!verify(temporaryFile, checksum)) {
                 Log.w(LOGTAG, "Checksum of extracted file does not match.");
                 return;
             }
 
             move(temporaryFile, destinationFile);
         } catch (IOException e) {
             // We could not extract to the destination: Keep temporary file and try again next time we run.