diff --git a/gui.c b/gui.c
index a310c2f..cb23bb3 100644
--- a/gui.c
+++ b/gui.c
@@ -384,6 +384,16 @@ struct osdmenu menus[] = { { "Main Menu",        LAST_ITEM(mainitems)-4, mainite
                            { "Overclock",        LAST_ITEM(ovopitems),  ovopitems },
                            { "Keyboard options", LAST_ITEM(keopitems),  keopitems }};
 
+#define MKPATH_MAX (1024)
+
+// Prepend file prefix to filename
+static void mkpath( char buf[MKPATH_MAX], const char *filename )
+{
+  strncpy( buf, get_fileprefix(), MKPATH_MAX );
+  buf[MKPATH_MAX-1] = 0;
+  strncat( buf, filename, MKPATH_MAX-strlen(buf)-1 );
+}
+
 // Load a 24bit BMP for the GUI
 SDL_bool gimg_load( struct guiimg *gi )
 {
@@ -391,9 +401,11 @@ SDL_bool gimg_load( struct guiimg *gi )
   Uint8 hdrbuf[640*3];
   Sint32 x, y;
   SDL_bool fileok;
+  char path[MKPATH_MAX];
 
   // Get the file
-  f = SDL_RWFromFile( gi->filename, "rb" );
+  mkpath( path, gi->filename );
+  f = SDL_RWFromFile( path, "rb" );
   if( !f )
   {
     error_printf( "Unable to open '%s'\n", gi->filename );
@@ -2196,44 +2208,45 @@ void swap_render_mode( struct machine *oric, struct osdmenuitem *mitem, int newr
   setemumode( oric, NULL, EM_RUNNING );
 }
 
-
 // Set things to default that can't fail
 void preinit_gui( struct machine *oric )
 {
   int i;
   for( i=0; i<NUM_TZ; i++ ) tz[i] = NULL;
   for( i=0; i<NUM_GIMG; i++ ) gimgs[i].buf = NULL;
-  strcpy( tapepath, FILEPREFIX"tapes" );
+  mkpath( tapepath, "tapes" );
   strcpy( tapefile, "" );
-  strcpy( diskpath, FILEPREFIX"disks" );
+  mkpath( diskpath, "disks" );
   strcpy( diskfile, "" );
-  strcpy( telediskpath, FILEPREFIX"teledisks" );
+  mkpath( telediskpath, "teledisks" );
   strcpy( telediskfile, "" );
-  strcpy( pravdiskpath, FILEPREFIX"pravdisks" );
+  mkpath( pravdiskpath, "pravdisks" );
   strcpy( pravdiskfile, "" );
-  strcpy( atmosromfile, ROMPREFIX"basic11b" );
-  strcpy( oric1romfile, ROMPREFIX"basic10" );
-  strcpy( mdiscromfile, ROMPREFIX"microdis" );
-  strcpy( bd500romfile, ROMPREFIX"bd500" );
-  strcpy( jasmnromfile, ROMPREFIX"jasmin" );
-  strcpy( pravetzromfile[0], ROMPREFIX"pravetzt" );
-  strcpy( pravetzromfile[1], ROMPREFIX"8dos2" );
+  mkpath( atmosromfile, ROMPREFIX"basic11b" );
+  mkpath( oric1romfile, ROMPREFIX"basic10" );
+  mkpath( mdiscromfile, ROMPREFIX"microdis" );
+  mkpath( bd500romfile, ROMPREFIX"bd500" );
+  mkpath( jasmnromfile, ROMPREFIX"jasmin" );
+  mkpath( pravetzromfile[0], ROMPREFIX"pravetzt" );
+  mkpath( pravetzromfile[1], ROMPREFIX"8dos2" );
   telebankfiles[0][0] = 0;
   telebankfiles[1][0] = 0;
   telebankfiles[2][0] = 0;
   telebankfiles[3][0] = 0;
   telebankfiles[4][0] = 0;
-  strcpy( telebankfiles[5], ROMPREFIX"teleass" );
-  strcpy( telebankfiles[6], ROMPREFIX"hyperbas" );
-  strcpy( telebankfiles[7], ROMPREFIX"telmon24" );
+  mkpath( telebankfiles[5], ROMPREFIX"teleass" );
+  mkpath( telebankfiles[6], ROMPREFIX"hyperbas" );
+  mkpath( telebankfiles[7], ROMPREFIX"telmon24" );
   set_render_mode( oric, RENDERMODE_NULL );
-  strcpy( snappath, FILEPREFIX"snapshots" );
+  mkpath( snappath, "snapshots" );
   strcpy( snapfile, "" );
-  strcpy( mappingpath, FILEPREFIX"keymap" );
+  mkpath( mappingpath, "keymap" );
   strcpy( mappingfile, "" );
 
 #ifndef __APPLE__
-  SDL_COMPAT_WM_SetIcon( SDL_LoadBMP( IMAGEPREFIX"winicon.bmp" ), NULL );
+  char path[MKPATH_MAX];
+  mkpath( path, IMAGEPREFIX"winicon.bmp" );
+  SDL_COMPAT_WM_SetIcon( SDL_LoadBMP( path ), NULL );
 #endif
 }
 
diff --git a/main.c b/main.c
index 578d097..03939e9 100644
--- a/main.c
+++ b/main.c
@@ -86,7 +86,7 @@ extern char jasmnromfile[];
 extern char pravetzromfile[2][1024];
 extern char telebankfiles[8][1024];
 
-static char keymap_path[4096+32];
+static char keymap_path[4096];
 static int  load_keymap = SDL_FALSE;
 
 struct context
@@ -178,6 +178,100 @@ static char *rendermodes[] = { "{{INVALID}}",
 
 static char *swdepths[] = { "8", "16", "32", NULL };
 
+static char *fileprefix = 0;
+
+// Initialize path prefix for locating program resources
+static void init_fileprefix( char *argv[] )
+{
+  (void) argv;
+#if defined(__amigaos4__)
+
+  fileprefix = "PROGDIR:";
+
+#elif defined(__ANDROID__)
+
+  fileprefix = "/data/data/com.emul.oricutron/files/";
+
+#elif defined(__linux__) || defined(__APPLE__)
+
+  // Find program directory
+  fileprefix = realpath( argv[0], 0 );           // convert to absolute path
+  int len = strlen( fileprefix );
+  while ( len && fileprefix[len-1] != PATHSEP )  // strip the program filename
+    len--;
+  fileprefix[len] = 0;
+
+#if defined(__APPLE__)
+  // When bundled, program is in <something>/Oricutron.app/Contents/MacOS/
+  // but data files are further up in the parent of Oricutron.app.
+  const char *suffix = ".app/Contents/MacOS/";
+  int suffix_len = strlen(suffix);
+  if ( len > suffix_len && !strcasecmp( fileprefix + len - suffix_len, suffix ) )
+  {
+     // Located in bundle - go to parent of .app dir
+     len -= suffix_len;                            // strip the suffix we matched
+     while ( len && fileprefix[len-1] != PATHSEP ) // strip the .app dir
+       len--;
+     fileprefix[len] = 0;
+  }
+  // else not bundled, stay in program directory
+#endif
+
+#else
+  fileprefix = "";
+#endif
+}
+
+// Get prefix string to locate program resources
+const char *get_fileprefix()
+{
+  return fileprefix;
+}
+
+// Check if filename looks to be absolute path
+SDL_bool is_abs_path( const char *filename )
+{
+  char c = *(filename++);
+
+  // Detect unix-style absolute path
+  if ( c == '/' || c == '\\' || c == '~' )
+    return SDL_TRUE;
+
+  // Detect Amiga style absolute path or DOS drive letter
+  while ( c )
+  {
+    if ( c == ':' )
+      return SDL_TRUE;
+    c = *(filename++);
+  }
+
+  return SDL_FALSE;
+}
+
+// Prepend file prefix to relative path, buffer of size maxlen
+void add_fileprefix( char *filename, int maxlen )
+{
+  const char *prefix = get_fileprefix();
+  Sint32 prefix_len = strlen( prefix );
+  if ( prefix_len == 0 )
+    return; // no file prefix on this platform
+
+  Sint32 filename_len = strlen( filename );
+  if ( prefix_len + filename_len + 1 > maxlen )
+    return; // won't fit in buffer
+
+  if ( is_abs_path ( filename ) )
+    return; // don't apply prefix to absolute path
+
+  // Move filename including terminating zero
+  for ( int i=filename_len+1; i>=0; i-- )
+    filename[prefix_len+i] = filename[i];
+
+  // Put the prefix before
+  for (int i=0; i<prefix_len; i++)
+    filename[i] = prefix[i];
+}
+
 static SDL_bool istokend( char c )
 {
   if( isws( c ) ) return SDL_TRUE;
@@ -232,6 +326,14 @@ SDL_bool read_config_string( char *buf, char *token, char *dest, Sint32 maxlen )
   return SDL_TRUE;
 }
 
+SDL_bool read_config_path( char *buf, char *token, char *dest, Sint32 maxlen )
+{
+  if ( !read_config_string( buf, token, dest, maxlen ) )
+    return SDL_FALSE;
+  add_fileprefix( dest, maxlen );
+  return SDL_TRUE;
+}
+
 SDL_bool read_config_bool( char *buf, char *token, SDL_bool *dest )
 {
   Sint32 i, toklen;
@@ -402,9 +504,11 @@ static void load_config( struct start_opts *sto, struct machine *oric )
   FILE *f;
   Sint32 i, j;
   char tbtmp[32];
-  char keymap_file[4096];
+  char config_path[4096];
 
-  f = fopen( FILEPREFIX"oricutron.cfg", "r" );
+  strcpy(config_path, "oricutron.cfg");
+  add_fileprefix(config_path, 4096);
+  f = fopen( config_path, "r" );
   if( !f ) return;
 
   while( !feof( f ) )
@@ -424,20 +528,20 @@ static void load_config( struct start_opts *sto, struct machine *oric )
     if( read_config_bool(   &sto->lctmp[i], "palghosting",  &oric->palghost ) ) continue;
     if( read_config_bool(   &sto->lctmp[i], "rom16",        &oric->rom16 ) ) continue;
     if( read_config_bool(   &sto->lctmp[i], "dos70",        &oric->dos70 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "diskimage",    sto->start_disk, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "tapeimage",    sto->start_tape, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "symbols",      sto->start_syms, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "tapepath",     tapepath, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "diskpath",     diskpath, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "telediskpath", telediskpath, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "pravdiskpath", pravdiskpath, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "atmosrom",     atmosromfile, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "oric1rom",     oric1romfile, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "mdiscrom",     mdiscromfile, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "bd500rom",     bd500romfile, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "jasminrom",    jasmnromfile, 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "pravetzrom",   pravetzromfile[0], 1024 ) ) continue;
-    if( read_config_string( &sto->lctmp[i], "pravetz8drom", pravetzromfile[1], 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "diskimage",    sto->start_disk, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "tapeimage",    sto->start_tape, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "symbols",      sto->start_syms, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "tapepath",     tapepath, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "diskpath",     diskpath, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "telediskpath", telediskpath, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "pravdiskpath", pravdiskpath, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "atmosrom",     atmosromfile, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "oric1rom",     oric1romfile, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "mdiscrom",     mdiscromfile, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "bd500rom",     bd500romfile, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "jasminrom",    jasmnromfile, 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "pravetzrom",   pravetzromfile[0], 1024 ) ) continue;
+    if( read_config_path(   &sto->lctmp[i], "pravetz8drom", pravetzromfile[1], 1024 ) ) continue;
     if( read_config_int(    &sto->lctmp[i], "rampattern",   &oric->rampattern, 0, 1 ) ) continue;
     if( read_config_option( &sto->lctmp[i], "swdepth",      &oric->sw_depth, swdepths ) )
     {
@@ -461,7 +565,7 @@ static void load_config( struct start_opts *sto, struct machine *oric )
     for( j=0; j<8; j++ )
     {
       sprintf( tbtmp, "telebank%c", j+'0' );
-      if( read_config_string( &sto->lctmp[i], tbtmp, telebankfiles[j], 1024 ) ) break;
+      if( read_config_path( &sto->lctmp[i], tbtmp, telebankfiles[j], 1024 ) ) break;
     }
     if( read_config_bool(   &sto->lctmp[i], "lightpen",     &oric->lightpen ) ) continue;
     if( read_config_bool(   &sto->lctmp[i], "printenable",  &oric->printenable ) ) continue;
@@ -533,10 +637,8 @@ static void load_config( struct start_opts *sto, struct machine *oric )
     if( read_config_bool(   &sto->lctmp[i], "disable_menuscheme", &oric->disable_menuscheme ) ) continue;
     if( read_config_bool(   &sto->lctmp[i], "show_keyboard", &oric->show_keyboard ) ) continue;
     if( read_config_bool(   &sto->lctmp[i], "sticky_mod_keys", &oric->sticky_mod_keys ) )continue;
-    if( read_config_string( &sto->lctmp[i], "autoload_keyboard_mapping", keymap_file, 4096 ) )
+    if( read_config_path(   &sto->lctmp[i], "autoload_keyboard_mapping", keymap_path, 4096 ) )
     {
-        strcpy(keymap_path, FILEPREFIX"");
-        strcat(keymap_path, keymap_file);
         load_keymap = SDL_TRUE;
         continue;
     }
@@ -1612,23 +1714,7 @@ int main( int argc, char *argv[] )
   putenv("SDL_VIDEO_CENTERED=center");
 #endif
 
-#ifdef __APPLE__
-  // --------------------------------------------------------------------
-  // This makes relative paths work in C++ in Xcode by changing directory
-  // to the Resources folder inside the .app bundle
-  CFBundleRef mainBundle = CFBundleGetMainBundle();
-  CFURLRef resourcesURL = CFBundleCopyResourcesDirectoryURL(mainBundle);
-  char path[PATH_MAX];
-  if (CFURLGetFileSystemRepresentation(resourcesURL, TRUE, (UInt8 *)path, PATH_MAX))
-  {
-    // this directory is something/Oricutron.app/Contents/Resources
-    // go down 3 times to find the app containing directory
-    strcat(path, "/../../..");
-    chdir(path);
-  }
-  CFRelease(resourcesURL);
-  //printf("Current Path: %s\n", path);
-#endif
+  init_fileprefix( argv );
 
   memset(&ctx.oric, 0, sizeof(ctx.oric));
   if (!init(&ctx.oric, argc, argv))
diff --git a/system.h b/system.h
index f254d6e..d92f86a 100644
--- a/system.h
+++ b/system.h
@@ -34,40 +34,18 @@
 /* Output audio frequency */
 #define AUDIO_FREQ   44100
 
-
-#if defined(__amigaos4__)
-
-#define PATHSEP '/'
-#define PATHSEPSTR "/"
-#define FILEPREFIX "PROGDIR:"
-#define ROMPREFIX "PROGDIR:roms/"
-#define IMAGEPREFIX "PROGDIR:images/"
-
-#elif defined(WIN32)
-
-#define PATHSEP '\\'
-#define PATHSEPSTR "\\"
-#define FILEPREFIX
-#define ROMPREFIX "roms\\"
-#define IMAGEPREFIX "images\\"
-
-#elif defined(__ANDROID__)
-
-#define PATHSEP '/'
-#define PATHSEPSTR "/"
-#define FILEPREFIX "/data/data/com.emul.oricutron/files/"
-#define ROMPREFIX FILEPREFIX"roms/"
-#define IMAGEPREFIX FILEPREFIX"images/"
-
+#if defined(WIN32)
+  #define PATHSEP '\\'
+  #define PATHSEPSTR "\\"
 #else
+  #define PATHSEP '/'
+  #define PATHSEPSTR "/"
+#endif
 
-#define PATHSEP '/'
-#define PATHSEPSTR "/"
-#define FILEPREFIX
-#define ROMPREFIX "roms/"
-#define IMAGEPREFIX "images/"
+#define ROMPREFIX "roms"PATHSEPSTR
+#define IMAGEPREFIX "images"PATHSEPSTR
 
-#endif
+const char *get_fileprefix();
 
 /* SDL related stuff */
 #include "system_sdl.h"