Use a different footer to announce the file type

agb-addr2line/src/load_dwarf.rs

@@ -13,19 +13,29 @@ pub fn load_dwarf(
         return load_from_object(&object);
     }
 
+    // the file might have been padded, so ensure we skip any padding before continuing
+    let last_non_zero_byte = file_content
+        .iter()
+        .rposition(|&b| b != 0)
+        .ok_or_else(|| anyhow::anyhow!("Gba file is empty"))?;
+
+    let file_content = &file_content[..last_non_zero_byte + 1];
+
     let last_8_bytes = &file_content[file_content.len() - 8..];
     let len = u32::from_le_bytes(last_8_bytes[0..4].try_into()?) as usize;
-    let version = u32::from_le_bytes(last_8_bytes[4..].try_into()?) as usize;
+    let version = &last_8_bytes[4..];
 
-    if version != 1 {
+    if version != b"agb1" {
-        bail!("Only version 1 of the debug info is supported");
+        bail!("Failed to load debug information from ROM file, it might not have been included?");
     }
 
     let compressed_debug_data = &file_content[file_content.len() - len - 8..file_content.len() - 8];
 
     let decompressing_reader =
         lz4_flex::frame::FrameDecoder::new(Cursor::new(compressed_debug_data));
-    let debug_info: HashMap<String, Vec<u8>> = rmp_serde::decode::from_read(decompressing_reader)?;
+    let debug_info: HashMap<String, Vec<u8>> =
+        rmp_serde::decode::from_read(decompressing_reader)
+            .map_err(|e| anyhow::anyhow!("Failed to load debug information: {e}"))?;
 
     let dwarf = gimli::Dwarf::load(|id| {
         let data = debug_info

agb-gbafix/src/lib.rs

@@ -173,7 +173,7 @@ fn write_debug<W: Write>(
 
     output.write_all(&debug_data)?;
     output.write_all(&(debug_data.len() as u32).to_le_bytes())?;
-    output.write_all(&(1u32).to_le_bytes())?;
+    output.write_all(b"agb1")?;
 
     Ok(debug_data.len() as u64 + 4)
 }