diff --git a/src/processor/memory.rs b/src/processor/memory.rs
index 1c9d81a..d565739 100644
--- a/src/processor/memory.rs
+++ b/src/processor/memory.rs
@@ -151,12 +151,20 @@ impl Memory {
                     }
                 }
                 0xFF04 => self.io[addr_l] = 0,
-                0xFF00 | 0xFF11 | 0xFF14 | 0xFF16 | 0xFF19 | 0xFF1E | 0xFF23 | 0xFF26 | 0xFF41
-                | 0xFF4D | 0xFF56 => {
+                0xFF00 => {
+                    // joypad
+                }
+                0xFF11 | 0xFF14 | 0xFF16 | 0xFF19 | 0xFF1E | 0xFF23 | 0xFF26 => {
+                    // sound
+                }
+                0xFF41 => {
                     // mixed read/write addresses...
                     // need to fill these out more...
                     // just seeing what breaks...
                 }
+                0xFF4D | 0xFF56 => {
+                    // cgb only
+                }
                 0xFF44 | 0xFF76 | 0xFF77 => {
                     // read-only addresses
                     println!("BANNED write: {:#X} to {:#X}", data, address);