diff --git a/src/basilisk/BasiliskII-worker-boot.js b/src/basilisk/BasiliskII-worker-boot.js
index d910b24..a481b59 100644
--- a/src/basilisk/BasiliskII-worker-boot.js
+++ b/src/basilisk/BasiliskII-worker-boot.js
@@ -27,7 +27,7 @@ function isCDImage(filename = '') {
 }
 
 function isDiskImage(filename = '') {
-  return filename.endsWith('.img') || filename.endsWith('.dsk');
+  return filename.endsWith('.img') || filename.endsWith('.dsk') || filename.endsWith('.hda');
 }
 
 function cleanupCopyPath() {