More R77 improvements.

- Don't allow ROM launcher to go above '/mnt/games'
- Remember 'lastrom' selected in ROM launcher

src/unix/FSNodePOSIX.cxx

@@ -15,6 +15,12 @@
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //============================================================================
 
+#if defined(RETRON77)
+  #define ROOT_DIR "/mnt/games/"
+#else
+  #define ROOT_DIR "/"
+#endif
+
 #include "FSNodePOSIX.hxx"
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -38,7 +44,7 @@ void FilesystemNodePOSIX::setFlags()
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 FilesystemNodePOSIX::FilesystemNodePOSIX()
-  : _path("/"),          // The root dir.
+  : _path(ROOT_DIR),
     _displayName(_path),
     _isValid(true),
     _isFile(false),
@@ -230,7 +236,7 @@ bool FilesystemNodePOSIX::rename(const string& newfile)
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 AbstractFSNodePtr FilesystemNodePOSIX::getParent() const
 {
-  if (_path == "/")
+  if (_path == ROOT_DIR)
     return nullptr;
 
   const char* start = _path.c_str();

src/unix/r77/SettingsR77.cxx

@@ -64,14 +64,15 @@ bool SettingsR77::saveConfigFile(const string& cfgfile) const
   // most of them.  This may also fix reported issues of the config file
   // becoming corrupt.
   //
-  // There is currently only one setting that can be changed - 'fullscreen'
-  // It determines whether to use 4:3 or 16:9 mode
+  // There are currently only a few settings that can be changed
+  // These will be expanded as more support is added
 
   ofstream out(cfgfile);
   if(!out || !out.is_open())
     return false;
 
   out << "fullscreen = " << getString("fullscreen") << endl;
+  out << "lastrom = " << getString("lastrom") << endl;
 
   out.flush();
   out.close();