diff --git a/src/bin/main.rs b/src/bin/main.rs
index 5fe3ea5..3aba732 100644
--- a/src/bin/main.rs
+++ b/src/bin/main.rs
@@ -1,14 +1,9 @@
 use std::ffi::OsStr;
-use std::fs::File;
-use std::io::prelude::*;
-use std::path::Path;
 use std::time;
 
 #[macro_use]
 extern crate clap;
 
-extern crate zip;
-
 use clap::{App, ArgMatches};
 
 extern crate rustboyadvance_ng;
@@ -20,25 +15,6 @@ use rustboyadvance_ng::core::{GBAError, GBAResult, GameBoyAdvance};
 use rustboyadvance_ng::debugger::Debugger;
 use rustboyadvance_ng::util::read_bin_file;
 
-fn load_rom(path: &str) -> GBAResult<Vec<u8>> {
-    if path.ends_with(".zip") {
-        let zipfile = File::open(path)?;
-        let mut archive = zip::ZipArchive::new(zipfile)?;
-        for i in 0..archive.len() {
-            let mut file = archive.by_index(i)?;
-            if file.name().ends_with(".gba") {
-                let mut buf = Vec::new();
-                file.read_to_end(&mut buf)?;
-                return Ok(buf);
-            }
-        }
-        panic!("no .gba file contained in the zip file");
-    } else {
-        let buf = read_bin_file(path)?;
-        Ok(buf)
-    }
-}
-
 fn run_emulator(matches: &ArgMatches) -> GBAResult<()> {
     let skip_bios = matches.occurrences_of("skip_bios") != 0;
     let no_framerate_limit = matches.occurrences_of("no_framerate_limit") != 0;
@@ -54,8 +30,7 @@ fn run_emulator(matches: &ArgMatches) -> GBAResult<()> {
 
     let bios_bin = read_bin_file(matches.value_of("bios").unwrap_or_default())?;
 
-    let rom_bin = load_rom(matches.value_of("game_rom").unwrap())?;
-    let cart = Cartridge::new(rom_bin);
+    let cart = Cartridge::from_path(matches.value_of("game_rom").unwrap())?;
     println!("loaded rom: {:#?}", cart.header);
 
     let mut core = Core::new();
diff --git a/src/core/cartridge.rs b/src/core/cartridge.rs
index f6a6f1c..4004d36 100644
--- a/src/core/cartridge.rs
+++ b/src/core/cartridge.rs
@@ -1,8 +1,14 @@
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::Path;
 use std::str::from_utf8;
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use zip::ZipArchive;
 
+use super::super::util::read_bin_file;
 use super::arm7tdmi::{bus::Bus, Addr};
+use super::GBAResult;
 
 /// From GBATEK
 ///
@@ -69,19 +75,40 @@ pub struct Cartridge {
     bytes: Box<[u8]>,
 }
 
+fn load_rom(path: &str) -> GBAResult<Vec<u8>> {
+    if path.ends_with(".zip") {
+        let zipfile = File::open(path)?;
+        let mut archive = ZipArchive::new(zipfile)?;
+        for i in 0..archive.len() {
+            let mut file = archive.by_index(i)?;
+            if file.name().ends_with(".gba") {
+                let mut buf = Vec::new();
+                file.read_to_end(&mut buf)?;
+                return Ok(buf);
+            }
+        }
+        panic!("no .gba file contained in the zip file");
+    } else {
+        let buf = read_bin_file(path)?;
+        Ok(buf)
+    }
+}
+
 impl Cartridge {
     const MIN_SIZE: usize = 4 * 1024 * 1024;
 
-    pub fn new(mut rom_bin: Vec<u8>) -> Cartridge {
+    pub fn from_path(rom_path: &str) -> GBAResult<Cartridge> {
+        let mut rom_bin = load_rom(rom_path)?;
+
         if rom_bin.len() < Cartridge::MIN_SIZE {
             rom_bin.resize_with(Cartridge::MIN_SIZE, Default::default);
         }
 
         let header = CartridgeHeader::parse(&rom_bin);
-        Cartridge {
+        Ok(Cartridge {
             header: header,
             bytes: rom_bin.into_boxed_slice(),
-        }
+        })
     }
 }