diff --git a/Core/display.c b/Core/display.c
index 57b7178..5208e54 100755
--- a/Core/display.c
+++ b/Core/display.c
@@ -266,8 +266,10 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
             gb->hdma_steps_left = 0xff;
         }
         
-        gb->oam_blocked = false;
-        gb->vram_blocked = false;
+        gb->oam_read_blocked = false;
+        gb->vram_read_blocked = false;
+        gb->oam_write_blocked = false;
+        gb->vram_write_blocked = false;
         
         /* Keep sending vblanks to user even if the screen is off */
         gb->display_cycles += cycles;
@@ -319,8 +321,11 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
             ly_for_comparison = gb->io_registers[GB_IO_LY] = 0;
             
             /* Todo: verify timing */
-            gb->oam_blocked = true;
-            gb->vram_blocked = false;
+            gb->oam_read_blocked = true;
+            gb->vram_read_blocked = false;
+            gb->oam_write_blocked = true;
+            gb->vram_write_blocked = false;
+
             
             /* Reset window rendering state */
             gb->current_window_line = 0xFF;
@@ -353,22 +358,28 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
         
         /* Handle line 0 right after turning the LCD on  */
         else if (gb->first_scanline) {
-            /* OAM and VRAM blocking is not delayed in the very first scanline */
+            /* OAM and VRAM blocking is not rushed in the very first scanline */
             if (gb->display_cycles == atomic_increase) {
                 gb->io_registers[GB_IO_STAT] &= ~3;
-                gb->oam_blocked = false;
-                gb->vram_blocked = false;
+                gb->oam_read_blocked = false;
+                gb->vram_read_blocked = false;
+                gb->oam_write_blocked = false;
+                gb->vram_write_blocked = false;
             }
             else if (gb->display_cycles == MODE2_LENGTH) {
                 gb->io_registers[GB_IO_STAT] &= ~3;
                 gb->io_registers[GB_IO_STAT] |= 3;
-                gb->oam_blocked = true;
-                gb->vram_blocked = true;
+                gb->oam_read_blocked = true;
+                gb->vram_read_blocked = true;
+                gb->oam_write_blocked = true;
+                gb->vram_write_blocked = true;
             }
             else if (gb->display_cycles == MODE2_LENGTH + MODE3_LENGTH) {
                 gb->io_registers[GB_IO_STAT] &= ~3;
-                gb->oam_blocked = false;
-                gb->vram_blocked = false;
+                gb->oam_read_blocked = false;
+                gb->vram_read_blocked = false;
+                gb->oam_write_blocked = false;
+                gb->vram_write_blocked = false;
             }
         }
         
@@ -377,13 +388,27 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
             unsigned position_in_line = gb->display_cycles % LINE_LENGTH;
             
             /* Handle OAM and VRAM blocking */
+            /* Todo: verify CGB timing for write blocking */
             if (position_in_line == stat_delay - oam_blocking_rush ||
                  // In case stat_delay is 0
                 (position_in_line == LINE_LENGTH + stat_delay - oam_blocking_rush && gb->io_registers[GB_IO_LY] != 143)) {
-                gb->oam_blocked = true;
+                gb->oam_read_blocked = true;
+                gb->oam_write_blocked = gb->is_cgb;
             }
             else if (position_in_line == MODE2_LENGTH + stat_delay - vram_blocking_rush) {
-                gb->vram_blocked = true;
+                gb->vram_read_blocked = true;
+                gb->vram_write_blocked = gb->is_cgb;
+            }
+            
+            if (position_in_line == stat_delay) {
+                gb->oam_write_blocked = true;
+            }
+            else if (!gb->is_cgb && position_in_line == MODE2_LENGTH + stat_delay - oam_blocking_rush) {
+                gb->oam_write_blocked = false;
+            }
+            else if (position_in_line == MODE2_LENGTH + stat_delay) {
+                gb->vram_write_blocked = true;
+                gb->oam_write_blocked = true;
             }
             
             /* Handle everything else */
@@ -411,8 +436,10 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
             }
             else if (position_in_line == MODE2_LENGTH + MODE3_LENGTH + stat_delay + scx_delay) {
                 gb->io_registers[GB_IO_STAT] &= ~3;
-                gb->vram_blocked = false;
-                gb->oam_blocked = false;
+                gb->oam_read_blocked = false;
+                gb->vram_read_blocked = false;
+                gb->oam_write_blocked = false;
+                gb->vram_write_blocked = false;
                 if (gb->hdma_on_hblank) {
                     gb->hdma_on = true;
                     gb->hdma_cycles = 0;
diff --git a/Core/gb.h b/Core/gb.h
index 6eca5f7..5448e5d 100644
--- a/Core/gb.h
+++ b/Core/gb.h
@@ -376,8 +376,10 @@ struct GB_gameboy_internal_s {
             GB_FRAMESKIP_SECOND_FRAME_RENDERED,
         } frame_skip_state;
         bool first_scanline; // The very first scan line after turning the LCD behaves differently.
-        bool oam_blocked;
-        bool vram_blocked;
+        bool oam_read_blocked;
+        bool vram_read_blocked;
+        bool oam_write_blocked;
+        bool vram_write_blocked;
     );
 
     /* Unsaved data. This includes all pointers, as well as everything that shouldn't be on a save state */
diff --git a/Core/memory.c b/Core/memory.c
index 36903df..4213585 100644
--- a/Core/memory.c
+++ b/Core/memory.c
@@ -60,7 +60,7 @@ static uint8_t read_mbc_rom(GB_gameboy_t *gb, uint16_t addr)
 
 static uint8_t read_vram(GB_gameboy_t *gb, uint16_t addr)
 {
-    if (gb->vram_blocked) {
+    if (gb->vram_read_blocked) {
         return 0xFF;
     }
     return gb->vram[(addr & 0x1FFF) + (uint16_t) gb->cgb_vram_bank * 0x2000];
@@ -115,7 +115,7 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
     }
 
     if (addr < 0xFEA0) {
-        if (gb->oam_blocked || (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
+        if (gb->oam_read_blocked || (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
             return 0xFF;
         }
         return gb->oam[addr & 0xFF];
@@ -338,7 +338,7 @@ static void write_mbc(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
 
 static void write_vram(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
 {
-    if (gb->vram_blocked) {
+    if (gb->vram_write_blocked) {
         //GB_log(gb, "Wrote %02x to %04x (VRAM) during mode 3\n", value, addr);
         return;
     }
@@ -385,7 +385,7 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
     }
 
     if (addr < 0xFEA0) {
-        if (gb->oam_blocked|| (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
+        if (gb->oam_write_blocked|| (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
             return;
         }
         gb->oam[addr & 0xFF] = value;