diff --git a/README.md b/README.md
index 1977aa5..be4304d 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,9 @@ Nintendo GameBoy Advance™ emulator and debugger, written in Rust.
 ## External content
 The file at [`external/gamecontrollerdb.txt`](./external/gamecontrollerdb.txt) is not my work - it is sourced from [this GitHub repository](https://github.com/mdqinc/SDL_GameControllerDB) and covered by the appropriate license present in said repository.
 
+## Usage
+You will need to specify the BIOS file to run with, using the `--bios` command-line argument. Note that there is such a BIOS ROM present in this directory at [`./external/gba_bios.bin`](./external/gba_bios.bin)
+
 ## Key bindings
 GBA key bindings:
 
diff --git a/app/src/options.rs b/app/src/options.rs
index a6bdfc6..c131cad 100644
--- a/app/src/options.rs
+++ b/app/src/options.rs
@@ -18,7 +18,7 @@ pub struct Options {
     pub rom: PathBuf,
 
     /// Bios file to use
-    #[structopt(long, parse(from_os_str), default_value = "gba_bios.bin")]
+    #[structopt(long, parse(from_os_str))]
     pub bios: PathBuf,
 
     /// Do not output sound