diff --git a/src/common/FSNodeZIP.cxx b/src/common/FSNodeZIP.cxx
index 0af148608..73c48aee0 100644
--- a/src/common/FSNodeZIP.cxx
+++ b/src/common/FSNodeZIP.cxx
@@ -18,6 +18,7 @@
 #include <set>
 
 #include "bspf.hxx"
+#include "Bankswitch.hxx"
 #include "OSystem.hxx"
 #include "FSNodeFactory.hxx"
 #include "FSNodeZIP.hxx"
@@ -38,14 +39,6 @@ FilesystemNodeZIP::FilesystemNodeZIP(const string& p)
     _isDirectory(false),
     _isFile(false)
 {
-  // Is this a valid file?
-  auto isFile = [](const string& file)
-  {
-    return BSPF::endsWithIgnoreCase(file, ".a26") ||
-           BSPF::endsWithIgnoreCase(file, ".bin") ||
-           BSPF::endsWithIgnoreCase(file, ".rom");
-  };
-
   // Extract ZIP file and virtual file (if specified)
   size_t pos = BSPF::findIgnoreCase(p, ".zip");
   if(pos == string::npos)
@@ -67,7 +60,7 @@ FilesystemNodeZIP::FilesystemNodeZIP(const string& p)
   if(pos+5 < p.length())
   {
     _virtualPath = p.substr(pos+5);
-    _isFile = isFile(_virtualPath);
+    _isFile = Bankswitch::isValidRomName(_virtualPath);
     _isDirectory = !_isFile;
   }
   else if(_numFiles == 1)
@@ -76,7 +69,7 @@ FilesystemNodeZIP::FilesystemNodeZIP(const string& p)
     while(zip.hasNext() && !found)
     {
       const string& file = zip.next();
-      if(isFile(file))
+      if(Bankswitch::isValidRomName(file))
       {
         _virtualPath = file;
         _isFile = true;
diff --git a/src/common/ZipHandler.cxx b/src/common/ZipHandler.cxx
index 673e5784e..903404a3e 100644
--- a/src/common/ZipHandler.cxx
+++ b/src/common/ZipHandler.cxx
@@ -19,6 +19,7 @@
 #include <cstdlib>
 #include <zlib.h>
 
+#include "Bankswitch.hxx"
 #include "ZipHandler.hxx"
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -261,13 +262,8 @@ ZipHandler::zip_error ZipHandler::zip_file_open(const char* filename, zip_file**
 
   // Count ROM files (we do it at this level so it will be cached)
   while(hasNext())
-  {
-    const std::string& file = next();
-    if(BSPF::endsWithIgnoreCase(file, ".a26") ||
-       BSPF::endsWithIgnoreCase(file, ".bin") ||
-       BSPF::endsWithIgnoreCase(file, ".rom"))
+    if(Bankswitch::isValidRomName(next()))
       (*zip)->romfiles++;
-  }
 
   return ZIPERR_NONE;
 
diff --git a/src/emucore/Bankswitch.cxx b/src/emucore/Bankswitch.cxx
index 4f8efca28..36efe39c8 100644
--- a/src/emucore/Bankswitch.cxx
+++ b/src/emucore/Bankswitch.cxx
@@ -49,9 +49,8 @@ Bankswitch::Type Bankswitch::typeFromExtension(const FilesystemNode& file)
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-bool Bankswitch::isValidRomName(const FilesystemNode& file, string& ext)
+bool Bankswitch::isValidRomName(const string& name, string& ext)
 {
-  const string& name = file.getPath();
   string::size_type idx = name.find_last_of('.');
   if(idx != string::npos)
   {
@@ -67,10 +66,23 @@ bool Bankswitch::isValidRomName(const FilesystemNode& file, string& ext)
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-bool Bankswitch::isValidRomName(const FilesystemNode& file)
+bool Bankswitch::isValidRomName(const FilesystemNode& name, string& ext)
 {
-  string extension;  // not actually used
-  return isValidRomName(file, extension);
+  return isValidRomName(name.getPath(), ext);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+bool Bankswitch::isValidRomName(const FilesystemNode& name)
+{
+  string ext;  // extension not used
+  return isValidRomName(name.getPath(), ext);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+bool Bankswitch::isValidRomName(const string& name)
+{
+  string ext;  // extension not used
+  return isValidRomName(name, ext);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/Bankswitch.hxx b/src/emucore/Bankswitch.hxx
index 7ec11596d..2f8b386c8 100644
--- a/src/emucore/Bankswitch.hxx
+++ b/src/emucore/Bankswitch.hxx
@@ -74,15 +74,17 @@ class Bankswitch
     /**
       Is this a valid ROM filename (does it have a valid extension?).
 
-      @param name  File node of potential ROM file
+      @param name  Filename of potential ROM file
       @param ext   The extension extracted from the given file
      */
-    static bool isValidRomName(const FilesystemNode& name, string& ext);
+    static bool isValidRomName(const string& name, string& ext);
 
     /**
-      Convenience function when extension isn't needed.
+      Convenience functions for different parameter types.
      */
+    static bool isValidRomName(const FilesystemNode& name, string& ext);
     static bool isValidRomName(const FilesystemNode& name);
+    static bool isValidRomName(const string& name);
 
   private:
     struct TypeComparator {