Read the local-header signature and fixed header together on the common seekable path, reducing reader calls for every entry. Short reads still validate the signature as soon as four bytes are available, preserving the existing error precedence for an invalid signature followed by a truncated header. In three single-worker uv unzip_wheel_many_files Callgrind runs, this reduced median instructions from 258.16M to 257.45M after the other parser optimizations, a further 0.28% reduction.