diff --git a/shared-bindings/displayio/TileGrid.c b/shared-bindings/displayio/TileGrid.c
index 6ba4914a02..53fbb51c89 100644
--- a/shared-bindings/displayio/TileGrid.c
+++ b/shared-bindings/displayio/TileGrid.c
@@ -131,7 +131,8 @@ STATIC mp_obj_t displayio_tilegrid_make_new(const mp_obj_type_t *type, size_t n_
 
     displayio_tilegrid_t *self = m_new_obj(displayio_tilegrid_t);
     self->base.type = &displayio_tilegrid_type;
-    common_hal_displayio_tilegrid_construct(self, native, bitmap_width / tile_width,
+    common_hal_displayio_tilegrid_construct(self, native,
+        bitmap_width / tile_width, bitmap_height / tile_height,
         pixel_shader, args[ARG_width].u_int, args[ARG_height].u_int,
         tile_width, tile_height, x, y, args[ARG_default_tile].u_int);
     return MP_OBJ_FROM_PTR(self);
@@ -346,7 +347,7 @@ STATIC mp_obj_t tilegrid_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t v
         }
         if (x >= common_hal_displayio_tilegrid_get_width(self) ||
                 y >= common_hal_displayio_tilegrid_get_height(self)) {
-            mp_raise_IndexError(translate("tile index out of bounds"));
+            mp_raise_IndexError(translate("Tile index out of bounds"));
         }
 
         if (value_obj == MP_OBJ_SENTINEL) {
@@ -357,7 +358,7 @@ STATIC mp_obj_t tilegrid_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t v
         } else {
             mp_int_t value = mp_obj_get_int(value_obj);
             if (value < 0 || value > 255) {
-                mp_raise_ValueError(translate("Tile indices must be 0 - 255"));
+                mp_raise_ValueError(translate("Tile value out of bounds"));
             }
             common_hal_displayio_tilegrid_set_tile(self, x, y, value);
         }
diff --git a/shared-bindings/displayio/TileGrid.h b/shared-bindings/displayio/TileGrid.h
index 1f9995a949..8227abfd37 100644
--- a/shared-bindings/displayio/TileGrid.h
+++ b/shared-bindings/displayio/TileGrid.h
@@ -32,7 +32,8 @@
 extern const mp_obj_type_t displayio_tilegrid_type;
 
 void common_hal_displayio_tilegrid_construct(displayio_tilegrid_t *self, mp_obj_t bitmap,
-        uint16_t bitmap_width_in_tiles, mp_obj_t pixel_shader, uint16_t width, uint16_t height,
+        uint16_t bitmap_width_in_tiles, uint16_t bitmap_height_in_tiles,
+        mp_obj_t pixel_shader, uint16_t width, uint16_t height,
         uint16_t tile_width, uint16_t tile_height, uint16_t x, uint16_t y, uint8_t default_tile);
 
 mp_int_t common_hal_displayio_tilegrid_get_x(displayio_tilegrid_t *self);
diff --git a/shared-module/displayio/Bitmap.c b/shared-module/displayio/Bitmap.c
index f8dc24c15e..59971d25cc 100644
--- a/shared-module/displayio/Bitmap.c
+++ b/shared-module/displayio/Bitmap.c
@@ -63,6 +63,11 @@ void common_hal_displayio_bitmap_construct(displayio_bitmap_t *self, uint32_t wi
     }
     self->x_mask = (1 << self->x_shift) - 1; // Used as a modulus on the x value
     self->bitmask = (1 << bits_per_value) - 1;
+
+    self->dirty_area.x1 = 0;
+    self->dirty_area.x2 = width;
+    self->dirty_area.y1 = 0;
+    self->dirty_area.y2 = height;
 }
 
 uint16_t common_hal_displayio_bitmap_get_height(displayio_bitmap_t *self) {
@@ -104,6 +109,26 @@ void common_hal_displayio_bitmap_set_pixel(displayio_bitmap_t *self, int16_t x,
     if (self->read_only) {
         mp_raise_RuntimeError(translate("Read-only object"));
     }
+    // Update the dirty area.
+    if (self->dirty_area.x1 == self->dirty_area.x2) {
+        self->dirty_area.x1 = x;
+        self->dirty_area.x2 = x + 1;
+        self->dirty_area.y1 = y;
+        self->dirty_area.y2 = y + 1;
+    } else {
+        if (x < self->dirty_area.x1) {
+            self->dirty_area.x1 = x;
+        } else if (x >= self->dirty_area.x2) {
+            self->dirty_area.x2 = x + 1;
+        }
+        if (y < self->dirty_area.y1) {
+            self->dirty_area.y1 = y;
+        } else if (y >= self->dirty_area.y2) {
+            self->dirty_area.y2 = y + 1;
+        }
+    }
+
+    // Update our data
     int32_t row_start = y * self->stride;
     uint32_t bytes_per_value = self->bits_per_value / 8;
     if (bytes_per_value < 1) {
@@ -124,3 +149,16 @@ void common_hal_displayio_bitmap_set_pixel(displayio_bitmap_t *self, int16_t x,
         }
     }
 }
+
+displayio_area_t* displayio_bitmap_get_refresh_areas(displayio_bitmap_t *self, displayio_area_t* tail) {
+    if (self->dirty_area.x1 == self->dirty_area.x2) {
+        return tail;
+    }
+    self->dirty_area.next = tail;
+    return &self->dirty_area;
+}
+
+void displayio_bitmap_finish_refresh(displayio_bitmap_t *self) {
+    self->dirty_area.x1 = 0;
+    self->dirty_area.x2 = 0;
+}
diff --git a/shared-module/displayio/Bitmap.h b/shared-module/displayio/Bitmap.h
index 48ca9e2cf6..f4bd7ce4d3 100644
--- a/shared-module/displayio/Bitmap.h
+++ b/shared-module/displayio/Bitmap.h
@@ -31,6 +31,7 @@
 #include <stdint.h>
 
 #include "py/obj.h"
+#include "shared-module/displayio/area.h"
 
 typedef struct {
     mp_obj_base_t base;
@@ -41,8 +42,12 @@ typedef struct {
     uint8_t bits_per_value;
     uint8_t x_shift;
     size_t x_mask;
+    displayio_area_t dirty_area;
     uint16_t bitmask;
     bool read_only;
 } displayio_bitmap_t;
 
+void displayio_bitmap_finish_refresh(displayio_bitmap_t *self);
+displayio_area_t* displayio_bitmap_get_refresh_areas(displayio_bitmap_t *self, displayio_area_t* tail);
+
 #endif // MICROPY_INCLUDED_SHARED_MODULE_DISPLAYIO_BITMAP_H
diff --git a/shared-module/displayio/TileGrid.c b/shared-module/displayio/TileGrid.c
index cdca45a29e..31abfb7123 100644
--- a/shared-module/displayio/TileGrid.c
+++ b/shared-module/displayio/TileGrid.c
@@ -26,6 +26,7 @@
 
 #include "shared-bindings/displayio/TileGrid.h"
 
+#include "py/runtime.h"
 #include "shared-bindings/displayio/Bitmap.h"
 #include "shared-bindings/displayio/ColorConverter.h"
 #include "shared-bindings/displayio/OnDiskBitmap.h"
@@ -33,7 +34,7 @@
 #include "shared-bindings/displayio/Shape.h"
 
 void common_hal_displayio_tilegrid_construct(displayio_tilegrid_t *self, mp_obj_t bitmap,
-        uint16_t bitmap_width_in_tiles,
+        uint16_t bitmap_width_in_tiles, uint16_t bitmap_height_in_tiles,
         mp_obj_t pixel_shader, uint16_t width, uint16_t height,
         uint16_t tile_width, uint16_t tile_height, uint16_t x, uint16_t y, uint8_t default_tile) {
     uint32_t total_tiles = width * height;
@@ -54,6 +55,7 @@ void common_hal_displayio_tilegrid_construct(displayio_tilegrid_t *self, mp_obj_
         self->inline_tiles = false;
     }
     self->bitmap_width_in_tiles = bitmap_width_in_tiles;
+    self->tiles_in_bitmap = bitmap_width_in_tiles * bitmap_height_in_tiles;
     self->width_in_tiles = width;
     self->height_in_tiles = height;
     self->x = x;
@@ -204,6 +206,9 @@ uint8_t common_hal_displayio_tilegrid_get_tile(displayio_tilegrid_t *self, uint1
 }
 
 void common_hal_displayio_tilegrid_set_tile(displayio_tilegrid_t *self, uint16_t x, uint16_t y, uint8_t tile_index) {
+    if (tile_index >= self->tiles_in_bitmap) {
+        mp_raise_ValueError(translate("Tile value out of bounds"));
+    }
     uint8_t* tiles = self->tiles;
     if (self->inline_tiles) {
         tiles = (uint8_t*) &self->tiles;
@@ -442,6 +447,14 @@ void displayio_tilegrid_finish_refresh(displayio_tilegrid_t *self) {
     } else if (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_colorconverter_type)) {
         displayio_colorconverter_finish_refresh(self->pixel_shader);
     }
+    if (MP_OBJ_IS_TYPE(self->bitmap, &displayio_bitmap_type)) {
+        displayio_bitmap_finish_refresh(self->bitmap);
+    } else if (MP_OBJ_IS_TYPE(self->bitmap, &displayio_shape_type)) {
+        // TODO: Support shape changes.
+    } else if (MP_OBJ_IS_TYPE(self->bitmap, &displayio_ondiskbitmap_type)) {
+        // OnDiskBitmap changes will trigger a complete reload so no need to
+        // track changes.
+    }
     // TODO(tannewt): We could double buffer changes to position and move them over here.
     // That way they won't change during a refresh and tear.
 }
@@ -458,8 +471,21 @@ displayio_area_t* displayio_tilegrid_get_refresh_areas(displayio_tilegrid_t *sel
         return &self->current_area;
     }
 
-    // We must recheck if our sources require a refresh because needs_refresh may or may not have
-    // been called.
+    // If we have an in-memory bitmap, then check it for modifications.
+    if (MP_OBJ_IS_TYPE(self->bitmap, &displayio_bitmap_type)) {
+        displayio_area_t* refresh_area = displayio_bitmap_get_refresh_areas(self->bitmap, tail);
+        if (refresh_area != tail) {
+            // Special case a TileGrid that shows a full bitmap and use it's
+            // dirty area. Copy it to ours so we can transform it.
+            if (self->tiles_in_bitmap == 1) {
+                displayio_area_copy(refresh_area, &self->dirty_area);
+                self->partial_change = true;
+            } else {
+                self->full_change = true;
+            }
+        }
+    }
+
     self->full_change = self->full_change ||
         (MP_OBJ_IS_TYPE(self->pixel_shader, &displayio_palette_type) &&
          displayio_palette_needs_refresh(self->pixel_shader)) ||
diff --git a/shared-module/displayio/TileGrid.h b/shared-module/displayio/TileGrid.h
index 4d97eccc2b..160b920dd9 100644
--- a/shared-module/displayio/TileGrid.h
+++ b/shared-module/displayio/TileGrid.h
@@ -41,7 +41,8 @@ typedef struct {
     int16_t y;
     uint16_t pixel_width;
     uint16_t pixel_height;
-    uint16_t bitmap_width_in_tiles;
+    uint16_t bitmap_width_in_tiles;;
+    uint8_t tiles_in_bitmap;
     uint16_t width_in_tiles;
     uint16_t height_in_tiles;
     uint16_t tile_width;
diff --git a/supervisor/shared/display.h b/supervisor/shared/display.h
index d5faa7777d..2a2ccf46df 100644
--- a/supervisor/shared/display.h
+++ b/supervisor/shared/display.h
@@ -35,11 +35,10 @@
 // These are autogenerated resources.
 
 // This is fixed so it doesn't need to be in RAM.
-extern const displayio_bitmap_t supervisor_terminal_font_bitmap;
-
 extern const fontio_builtinfont_t supervisor_terminal_font;
 
 // These will change so they must live in RAM.
+extern displayio_bitmap_t supervisor_terminal_font_bitmap;
 extern displayio_tilegrid_t supervisor_terminal_text_grid;
 extern terminalio_terminal_obj_t supervisor_terminal;
 
diff --git a/tools/gen_display_resources.py b/tools/gen_display_resources.py
index 2c674c8ebd..9707b210ca 100644
--- a/tools/gen_display_resources.py
+++ b/tools/gen_display_resources.py
@@ -122,6 +122,7 @@ displayio_tilegrid_t supervisor_terminal_text_grid = {{
     .pixel_width = {1},
     .pixel_height = {2},
     .bitmap_width_in_tiles = {0},
+    .tiles_in_bitmap = {0},
     .width_in_tiles = 1,
     .height_in_tiles = 1,
     .tile_width = {1},
@@ -150,7 +151,7 @@ c_file.write("""\
 """)
 
 c_file.write("""\
-const displayio_bitmap_t supervisor_terminal_font_bitmap = {{
+displayio_bitmap_t supervisor_terminal_font_bitmap = {{
     .base = {{.type = &displayio_bitmap_type }},
     .width = {},
     .height = {},