small fixes

fast64_internal/sm64/sm64_utility.py

@@ -212,7 +212,7 @@ def find_descriptor_in_text(value: ModifyFoundDescriptor, commentless: str, comm
 
         header_pos = 0
         if len(header_matches) > 0:
-            _, header_pos, _ = header_matches[-1]
+            _, header_pos, _ = header_matches[0]
         elif error_if_no_header:
             raise PluginError(f"Header {header.string} does not exist.")
 
@@ -221,7 +221,10 @@ def find_descriptor_in_text(value: ModifyFoundDescriptor, commentless: str, comm
         if footer_pos is None:
             if error_if_no_footer:
                 raise PluginError(f"Footer {footer.string} does not exist.")
-            footer_pos = len(text)
+            if len(footer_matches) > 0:
+                _, footer_pos, _ = footer_matches[-1]
+            else:
+                footer_pos = len(text)
 
         for descriptor in to_add + to_remove:
             matches = find_descriptor_in_text(descriptor, commentless[header_pos:footer_pos], comment_map)