diff --git a/App/lib/core/IncludesScanner.vp b/App/lib/core/IncludesScanner.vp
index d194fc6..ef4651a 100644
--- a/App/lib/core/IncludesScanner.vp
+++ b/App/lib/core/IncludesScanner.vp
@@ -155,7 +155,9 @@ def compute_file_sha1(pool: memhub.MemBuddy | t.CPtr,
         return None
 
     # 读取文件内容（stdlib.malloc 分配，避免 mbuddy 池耗尽）
-    BUF_SIZE: t.CSizeT = 131072
+    # BUF_SIZE 与翻译侧 SRC_BUF_SIZE（1MB）一致：若截断到 128KB，
+    # 超过 128KB 的文件尾部内容变更不会改变 SHA1 → 增量缓存永不失效。
+    BUF_SIZE: t.CSizeT = 1048576
     buf: bytes = Utils.read_file_to_buf(file_path, BUF_SIZE)
     if buf is None:
         return None
diff --git a/App/lib/core/Phase2.vp b/App/lib/core/Phase2.vp
index 53575b8..6f7dae1 100644
--- a/App/lib/core/Phase2.vp
+++ b/App/lib/core/Phase2.vp
@@ -124,7 +124,11 @@ def _ScanDirForPyFiles(mb: memhub.MemBuddy | t.CPtr,
                                     if full_path is not None:
                                         sbuf: bytes = Utils.read_file_to_buf(full_path, SRC_BUF_SIZE)
                                         if sbuf is not None:
-                                            sha1_val: str = Utils.compute_sha1(mb, sbuf)
+                                            # 统一用 IncludesScanner.compute_file_sha1（CRLF→LF 归一化），
+                                            # 与 StubMerger.vp:1510 对同一批 App 源文件的口径一致；
+                                            # 此前用 Utils.compute_sha1（原始字节）会导致 stub/define
+                                            # 符号前缀不一致 → 链接报 undefined reference。
+                                            sha1_val: str = IncludesScanner.compute_file_sha1(mb, full_path)
                                             if sha1_val is not None:
                                                 ea: t.CUInt64T = t.CUInt64T(entries) + file_count * entry_size
                                                 ent: SrcFileEntry | t.CPtr = (SrcFileEntry | t.CPtr)(t.CVoid(ea, t.CPtr))