diff --git a/src/i_video.c b/src/i_video.c
index a23a2a48..83dcd86f 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -884,6 +884,7 @@ static int actualheight;
 
 int uncapped; // [FG] uncapped rendering frame rate
 int integer_scaling; // [FG] force integer scales
+int vga_porch_flash; // emulate VGA "porch" behaviour
 int fps; // [FG] FPS counter widget
 int widescreen; // widescreen mode
 
@@ -1111,6 +1112,15 @@ void I_SetPalette(byte *palette)
    }
    
    SDL_SetPaletteColors(sdlscreen->format->palette, colors, 0, 256);
+
+   if (vga_porch_flash)
+   {
+      // "flash" the pillars/letterboxes with palette changes,
+      // emulating VGA "porch" behaviour
+      SDL_SetRenderDrawColor(renderer,
+                             colors[0].r, colors[0].g, colors[0].b,
+                             SDL_ALPHA_OPAQUE);
+   }
 }
 
 // Taken from Chocolate Doom chocolate-doom/src/i_video.c:L841-867
diff --git a/src/i_video.h b/src/i_video.h
index 0f0a07e0..89a81625 100644
--- a/src/i_video.h
+++ b/src/i_video.h
@@ -81,6 +81,7 @@ extern int hires;      // killough 11/98
 extern int useaspect;
 extern int uncapped; // [FG] uncapped rendering frame rate
 extern int integer_scaling; // [FG] force integer scales
+extern int vga_porch_flash; // emulate VGA "porch" behaviour
 extern int widescreen; // widescreen mode
 extern int video_display; // display index
 extern int window_width, window_height;
diff --git a/src/m_misc.c b/src/m_misc.c
index 502141ae..f3db21c7 100644
--- a/src/m_misc.c
+++ b/src/m_misc.c
@@ -2344,6 +2344,13 @@ default_t defaults[] = {
     "1 to force integer scales"
   },
 
+  {
+    "vga_porch_flash",
+    (config_t *) &vga_porch_flash, NULL,
+    {0}, {0, 1}, number, ss_none, wad_no,
+    "1 to emulate VGA \"porch\" behaviour"
+  },
+
   // widescreen mode
   {
     "widescreen",