diff --git a/src/machine/m_tandy.c b/src/machine/m_tandy.c
index 6c478b37a..bc20a4510 100644
--- a/src/machine/m_tandy.c
+++ b/src/machine/m_tandy.c
@@ -864,7 +864,23 @@ vid_in(uint16_t addr, void *priv)
             break;
 
         case 0x03d5:
-            ret = vid->crtc[vid->crtcreg];
+            switch (vid->crtcreg) {
+                default:
+                    ret = vid->crtc[vid->crtcreg];
+                    break;
+                case 0x10:
+                    if (dev->is_sl2)
+                        ret = vid->crtc[vid->crtcreg];
+                    else
+                        ret = 0x0f;
+                    break;
+                case 0x11:
+                    if (dev->is_sl2)
+                        ret = vid->crtc[vid->crtcreg];
+                    else
+                        ret = 0x78;
+                    break;
+            }
             break;
 
         case 0x03da:
diff --git a/src/video/vid_cga.c b/src/video/vid_cga.c
index 2ea07c346..b5590c2c0 100644
--- a/src/video/vid_cga.c
+++ b/src/video/vid_cga.c
@@ -131,7 +131,17 @@ cga_in(uint16_t addr, void *priv)
             ret = cga->crtcreg;
             break;
         case 0x3D5:
-            ret = cga->crtc[cga->crtcreg];
+            switch (cga->crtcreg) {
+                default:
+                    ret = cga->crtc[cga->crtcreg];
+                    break;
+                case 0x10:
+                    ret = 0x0f;
+                    break;
+                case 0x11:
+                    ret = 0x78;
+                    break;
+            }
             break;
         case 0x3DA:
             ret = cga->cgastat;