diff --git a/boy-debug/src/bus.rs b/boy-debug/src/bus.rs
index 04ff8f1..1d2ada5 100644
--- a/boy-debug/src/bus.rs
+++ b/boy-debug/src/bus.rs
@@ -8,7 +8,7 @@ pub trait BusIOTools: BusIO {
     /// Prints all successful reads and writes
     fn trace(&mut self) -> TracingBus<Self>;
     fn ascii(&mut self) -> AsciiSerial<Self>;
-    fn read_file(self, path: impl AsRef<Path>) -> IoResult<Self>
+    fn read_file(&mut self, path: impl AsRef<Path>) -> IoResult<&mut Self>
     where
         Self: Sized;
 }
@@ -24,7 +24,7 @@ impl<T: BusIO> BusIOTools for T {
             bus: self,
         }
     }
-    fn read_file(mut self, path: impl AsRef<Path>) -> IoResult<Self> {
+    fn read_file(&mut self, path: impl AsRef<Path>) -> IoResult<&mut Self> {
         let data = std::fs::read(path)?;
         eprintln!("Read {} bytes.", data.len());
         for (addr, data) in data.into_iter().enumerate() {
diff --git a/boy-debug/src/main.rs b/boy-debug/src/main.rs
index 7fd6061..fbb479a 100644
--- a/boy-debug/src/main.rs
+++ b/boy-debug/src/main.rs
@@ -9,18 +9,17 @@ use boy_debug::{
     message::Response,
 };
 use rustyline::{config::Configurer, history::FileHistory, Editor};
-use std::error::Error;
+use std::{env::args, error::Error};
 
 fn main() -> Result<(), Box<dyn Error>> {
     // Set up the gameboy
     // TODO: move off the main thread
-    let args: Vec<_> = std::env::args().collect();
-    let mut bus = match args.len() {
-        2 => vec![0; 0x10000].read_file(&args[1])?,
-        _ => return Err(format!("Usage: {} [rom.gb]", args[0]).into()),
-    };
+    let mut bus = vec![0; 0x10000];
+    for arg in std::env::args().skip(1) {
+        bus.read_file(arg)?;
+    }
     // let mut bus = Bus::new(Cart::new(bus));
-    let mut gb = Gameboy::new(bus.ascii());
+    let mut gb = Gameboy::new(bus);
 
     // Set up and run the REPL
     let mut rl: Editor<(), FileHistory> = Editor::new()?;