diff --git a/src/devices/graphical_debug/debug.rs b/src/devices/graphical_debug/debug.rs
index 4b684c8a..e3fe0472 100644
--- a/src/devices/graphical_debug/debug.rs
+++ b/src/devices/graphical_debug/debug.rs
@@ -29,0 +30,3 @@ impl DebugDisplay {
+    const CHAR_WIDTH: usize = 8;
+    const CHAR_HEIGHT: usize = 16;
+
@@ -43,2 +46,2 @@ impl DebugDisplay {
-        let w = display.width / 8;
-        let h = display.height / 16;
+        let w = display.width / Self::CHAR_WIDTH;
+        let h = display.height / Self::CHAR_HEIGHT;
@@ -54,0 +58,21 @@ impl DebugDisplay {
+    fn scroll_up(&mut self) {
+        let stride = self.display.stride;
+        let width = self.display.width;
+        let total_height = self.display.height;
+        let scroll_px = Self::CHAR_HEIGHT;
+
+        unsafe {
+            let ptr = self.display.onscreen_ptr;
+            for row in 0..total_height - scroll_px {
+                ptr::copy(
+                    ptr.add((row + scroll_px) * stride),
+                    ptr.add(row * stride),
+                    width,
+                );
+            }
+            for row in total_height - scroll_px..total_height {
+                ptr::write_bytes(ptr.add(row * stride), 0, width);
+            }
+        }
+    }
+
@@ -59 +83,5 @@ impl DebugDisplay {
-                self.y = (self.y + 1) % self.h;
+                self.y += 1;
+                if self.y >= self.h {
+                    self.scroll_up();
+                    self.y = self.h - 1;
+                }
@@ -67 +94,0 @@ impl DebugDisplay {
-                // Byte 0x1B starts ESC sequence
@@ -72 +98,0 @@ impl DebugDisplay {
-                // Ignore other nonprintable characters
@@ -77 +102,0 @@ impl DebugDisplay {
-                // '[' after ESC starts CSI sequence
@@ -82 +106,0 @@ impl DebugDisplay {
-                // Capture any bytes after ESC
@@ -87 +110,0 @@ impl DebugDisplay {
-                // Byte 0x40 to 0x7E ends CSI
@@ -92 +114,0 @@ impl DebugDisplay {
-                // Capture any bytes after CSI
@@ -96 +117,0 @@ impl DebugDisplay {
-                // Allow any other bytes
@@ -102 +122,0 @@ impl DebugDisplay {
-                self.clear_row((self.y + 1) % self.h);
@@ -105 +125 @@ impl DebugDisplay {
-            self.char(self.x * 8, self.y * 16, b as char, 0xFFFFFF);
+            self.char(self.x * Self::CHAR_WIDTH, self.y * Self::CHAR_HEIGHT, b as char, 0xFFFFFF);
@@ -112 +132 @@ impl DebugDisplay {
-        for row in y * 16..(y + 1) * 16 {
+        for row in y * Self::CHAR_HEIGHT..(y + 1) * Self::CHAR_HEIGHT {
@@ -123 +142,0 @@ impl DebugDisplay {
-    /// Draw a character
@@ -125,7 +144,8 @@ impl DebugDisplay {
-        if x + 8 <= self.display.width && y + 16 <= self.display.height {
-            let phys_y = y % self.display.height;
-            let mut dst = unsafe {
-                self.display
-                    .onscreen_ptr
-                    .add(phys_y * self.display.stride + x)
-            };
+        if x + Self::CHAR_WIDTH > self.display.width || y + Self::CHAR_HEIGHT > self.display.height {
+            return;
+        }
+
+        let font_i = Self::CHAR_HEIGHT * (character as usize);
+        if font_i + Self::CHAR_HEIGHT > FONT.len() {
+            return;
+        }
@@ -133,6 +152,0 @@ impl DebugDisplay {
-            let font_i = 16 * (character as usize);
-            if font_i + 16 <= FONT.len() {
-                for row in 0..16 {
-                    let row_data = FONT[font_i + row];
-                    for col in 0..8 {
-                        if (row_data >> (7 - col)) & 1 == 1 {
@@ -139,0 +154,7 @@ impl DebugDisplay {
+            let ptr = self.display.onscreen_ptr;
+            let stride = self.display.stride;
+            for row in 0..Self::CHAR_HEIGHT {
+                let row_data = FONT[font_i + row];
+                let dst = ptr.add((y + row) * stride + x);
+                for col in 0..Self::CHAR_WIDTH {
+                    if (row_data >> (Self::CHAR_WIDTH - 1 - col)) & 1 == 1 {
@@ -144,9 +164,0 @@ impl DebugDisplay {
-
-                    let next_phys_y = (phys_y + row + 1) % self.display.height;
-                    dst = unsafe {
-                        self.display
-                            .onscreen_ptr
-                            .add(next_phys_y * self.display.stride + x)
-                    };
-                }
-            }