diff --git a/build.rs b/build.rs
index e427bf40b69c1d256a03a4d9784baac1869693a8..34817de23a50e880a9c39f3e18ab2df320baae18 100644
--- a/build.rs
+++ b/build.rs
@@ -39,5 +39,5 @@ fn handle_image(name: &str) {
     let out_dir = env::var("OUT_DIR").unwrap();
 
     let mut f = File::create(Path::new(&out_dir).join(format!("{name}.bin"))).unwrap();
-    f.write_all(&out.as_raw_slice()).unwrap();
+    f.write_all(out.as_raw_slice()).unwrap();
 }
diff --git a/src/lib.rs b/src/lib.rs
index e72d8881abb9019b02fae571d4b2ff7f312e28c4..9a785b990afb110ffc8734a18de034c960632675 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,8 +3,10 @@ use bitvec::{order::Msb0, view::BitView};
 const WIDTH: i32 = 96;
 const HEIGHT: i32 = 38;
 
+/// # Safety
+/// `ptr` must point to a 456-byte chunk of memory
 #[no_mangle]
-pub extern "C" fn next_frame(frame: u16, ptr: *mut u8) -> u8 {
+pub unsafe extern "C" fn next_frame(frame: u16, ptr: *mut u8) -> u8 {
     let out = unsafe { std::slice::from_raw_parts_mut(ptr, 456) };
     out.fill(0);
     let out = out.view_bits_mut::<Msb0>();
diff --git a/src/main.rs b/src/main.rs
index aaaac7d4f616ee223850e4977a3230daa8ae9612..e050456bcc7a49e2264af4c5eff464a0c9eb69be 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,7 +24,7 @@ fn main() {
             thread::sleep(target - now);
         }
 
-        if next_frame(i, frame.as_mut_ptr()) == 1 {
+        if unsafe { next_frame(i, frame.as_mut_ptr()) } == 1 {
             break;
         }