diff --git a/src/interconnect.rs b/src/interconnect.rs
index d84cf40..7430cd0 100644
--- a/src/interconnect.rs
+++ b/src/interconnect.rs
@@ -265,14 +265,14 @@ impl Interconnect {
         // TODO: if some flag set, use bios, otherwise only use rom
         // For now, just use bios
         match addr {
-            0x0000..=0x100 => {
-                if self.disable_bootrom == 0 {
+            0x0000..=0x0FF | 0x200..=0x8FF => {
+                if self.disable_bootrom == 0 && self.bios.len() > addr as usize {
                     self.bios[addr as usize]
                 } else {
                     self.cartridge.read_byte(addr)
                 }
             }
-            0x100..=0x7FFF => self.cartridge.read_byte(addr),
+            0x100..=0x1FF | 0x900..=0x7FFF => self.cartridge.read_byte(addr),
             0x8000..=0x9FFF => self.display.read_byte(addr),
             0xA000..=0xBFFF => self.cartridge.read_byte(addr),
             0xC000..=0xCFFF => self.ram[(addr - 0xC000) as usize],