diff --git a/src/devices/screen.c b/src/devices/screen.c
index 7c2f81c..0789045 100644
--- a/src/devices/screen.c
+++ b/src/devices/screen.c
@@ -24,7 +24,7 @@ static Uint8 blending[4][16] = {
 	{1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1},
 	{2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2}};
 
-static void
+void
 screen_change(Uint16 x1, Uint16 y1, Uint16 x2, Uint16 y2)
 {
 	if(x1 > uxn_screen.width && x2 > x1) return;
@@ -129,6 +129,40 @@ screen_redraw(void)
 	uxn_screen.x1 = uxn_screen.y1 = uxn_screen.x2 = uxn_screen.y2 = 0;
 }
 
+/* clang-format off */
+
+Uint8 icons[] = {
+	0x00, 0x7c, 0x82, 0x82, 0x82, 0x82, 0x82, 0x7c, 0x00, 0x30, 0x10, 0x10, 0x10, 0x10, 0x10, 
+	0x10, 0x00, 0x7c, 0x82, 0x02, 0x7c, 0x80, 0x80, 0xfe, 0x00, 0x7c, 0x82, 0x02, 0x1c, 0x02, 
+	0x82, 0x7c, 0x00, 0x0c, 0x14, 0x24, 0x44, 0x84, 0xfe, 0x04, 0x00, 0xfe, 0x80, 0x80, 0x7c, 
+	0x02, 0x82, 0x7c, 0x00, 0x7c, 0x82, 0x80, 0xfc, 0x82, 0x82, 0x7c, 0x00, 0x7c, 0x82, 0x02, 
+	0x1e, 0x02, 0x02, 0x02, 0x00, 0x7c, 0x82, 0x82, 0x7c, 0x82, 0x82, 0x7c, 0x00, 0x7c, 0x82, 
+	0x82, 0x7e, 0x02, 0x82, 0x7c, 0x00, 0x7c, 0x82, 0x02, 0x7e, 0x82, 0x82, 0x7e, 0x00, 0xfc, 
+	0x82, 0x82, 0xfc, 0x82, 0x82, 0xfc, 0x00, 0x7c, 0x82, 0x80, 0x80, 0x80, 0x82, 0x7c, 0x00, 
+	0xfc, 0x82, 0x82, 0x82, 0x82, 0x82, 0xfc, 0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x82, 0x7c,
+	0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x80, 0x80};
+
+/* clang-format on */
+
+void
+draw_byte(Uint8 v, Uint16 x, Uint16 y, Uint8 color)
+{
+	screen_blit(uxn_screen.fg, icons, v >> 4 << 3, x, y, color, 0, 0, 0);
+	screen_blit(uxn_screen.fg, icons, (v & 0xf) << 3, x + 8, y, color, 0, 0, 0);
+}
+
+void
+screen_debugger(Uxn *u)
+{
+	int i;
+	for(i = 0; i < u->wst.ptr; i++)
+		draw_byte(u->wst.dat[i], i * 0x18 + 0x8, uxn_screen.height - 0x18, 0x2);
+	for(i = 0; i < u->rst.ptr; i++)
+		draw_byte(u->rst.dat[i], i * 0x18 + 0x8, uxn_screen.height - 0x10, 0x3);
+	for(i = 0; i < 0x40; i++)
+		draw_byte(u->ram[i], (i & 0x7) * 0x18 + 0x8, ((i >> 3) << 3) + 0x8, 1 + !!u->ram[i]);
+}
+
 Uint8
 screen_dei(Uxn *u, Uint8 addr)
 {
diff --git a/src/devices/screen.h b/src/devices/screen.h
index 6a417a3..6620909 100644
--- a/src/devices/screen.h
+++ b/src/devices/screen.h
@@ -21,6 +21,8 @@ extern int emu_resize(int width, int height);
 
 void screen_palette(Uint8 *addr);
 void screen_resize(Uint16 width, Uint16 height);
+void screen_change(Uint16 x1, Uint16 y1, Uint16 x2, Uint16 y2);
 void screen_redraw(void);
+void screen_debugger(Uxn *u);
 Uint8 screen_dei(Uxn *u, Uint8 addr);
 void screen_deo(Uint8 *ram, Uint8 *d, Uint8 port);
diff --git a/src/uxn.c b/src/uxn.c
index 46c0d8b..18e4ba3 100644
--- a/src/uxn.c
+++ b/src/uxn.c
@@ -12,7 +12,7 @@ WITH REGARD TO THIS SOFTWARE.
 */
 
 #define HALT(c)    { return emu_halt(u, ins, (c), pc - 1); }
-#define FLIP       { s = (ins & 0x40) ? &u->wst : &u->rst; }
+#define FLIP       { s = ins & 0x40 ? &u->wst : &u->rst; }
 #define JUMP(x)    { if(m2) pc = (x); else pc += (Sint8)(x); }
 #define POKE(x, y) { if(m2) { POKE2(ram + x, y) } else { ram[(x)] = (y); } }
 #define PEEK(o, x) { if(m2) { o = PEEK2(ram + x); } else o = ram[(x)]; }
@@ -23,7 +23,7 @@ WITH REGARD TO THIS SOFTWARE.
 #define POP2(o)    { if((tsp = *sp) <= 0x01) HALT(1) o = PEEK2(&s->dat[tsp - 2]); *sp = tsp - 2; }
 #define POPx(o)    { if(m2) { POP2(o) } else { POP1(o) } }
 #define DEVW(p, y) { if(m2) { DEO(p, y >> 8) DEO((p + 1), y) } else { DEO(p, y) } }
-#define DEVR(o, p) { if(m2) { o = ((DEI(p) << 8) + DEI(p + 1)); } else { o = DEI(p); } }
+#define DEVR(o, p) { if(m2) { o = DEI(p) << 8 | DEI(p + 1); } else { o = DEI(p); } }
 
 int
 uxn_eval(Uxn *u, Uint16 pc)
@@ -47,7 +47,7 @@ uxn_eval(Uxn *u, Uint16 pc)
 		case -0x2: /* JMI   */ pc += PEEK2(ram + pc) + 2; break;
 		case -0x3: /* JSI   */ PUSH2(pc + 2) pc += PEEK2(ram + pc) + 2; break;
 		case -0x4: /* LIT   */
-		case -0x6: /* LITr  */ a = ram[pc++]; PUSH1(a) break;
+		case -0x6: /* LITr  */ PUSH1(ram[pc++]) break;
 		case -0x5: /* LIT2  */
 		case -0x7: /* LIT2r */ PUSH2(PEEK2(ram + pc)) pc += 2; break;
 		/* ALU */
diff --git a/src/uxn.h b/src/uxn.h
index 367b920..8bb5831 100644
--- a/src/uxn.h
+++ b/src/uxn.h
@@ -15,7 +15,7 @@ WITH REGARD TO THIS SOFTWARE.
 
 #define POKE2(d, v) { (d)[0] = (v) >> 8; (d)[1] = (v); }
 #define PEEK2(d) ((d)[0] << 8 | (d)[1])
-#define DEO(p, value) { u->dev[p] = value; if((deo_mask[p >> 4] >> (p & 0xf)) & 0x1) emu_deo(u, p); }
+#define DEO(p, v) { u->dev[p] = v; if((deo_mask[p >> 4] >> (p & 0xf)) & 0x1) emu_deo(u, p); }
 #define DEI(p) ((dei_mask[(p) >> 4] >> ((p) & 0xf)) & 0x1 ? emu_dei(u, (p)) : u->dev[(p)])
 
 /* clang-format on */
diff --git a/src/uxn11.c b/src/uxn11.c
index ac8e618..7af02c7 100644
--- a/src/uxn11.c
+++ b/src/uxn11.c
@@ -143,7 +143,7 @@ emu_event(Uxn *u)
 		char buf[7];
 		XLookupString((XKeyPressedEvent *)&ev, buf, 7, &sym, 0);
 		if(sym == XK_F2)
-			system_inspect(u);
+			u->dev[0x0e] = !u->dev[0x0e];
 		if(sym == XK_F4)
 			if(!emu_start(u, "boot.rom"))
 				emu_start(u, rom_path);
@@ -247,6 +247,8 @@ main(int argc, char **argv)
 		if(uxn_screen.x2) {
 			int x1 = uxn_screen.x1, y1 = uxn_screen.y1, x2 = uxn_screen.x2, y2 = uxn_screen.y2;
 			screen_redraw();
+			if(u.dev[0x0e])
+				screen_debugger(&u);
 			XPutImage(display, window, DefaultGC(display, 0), ximage, x1, y1, x1 + PAD, y1 + PAD, x2 - x1, y2 - y1);
 		}
 	}