diff --git a/gnu/packages/patches/python-3-deterministic-build-info.patch b/gnu/packages/patches/python-3-deterministic-build-info.patch
index 22c372a..bdf9f20 100644
--- a/gnu/packages/patches/python-3-deterministic-build-info.patch
+++ b/gnu/packages/patches/python-3-deterministic-build-info.patch
@@ -15,3 +15,28 @@ We cannot pass it in CPPFLAGS due to whitespace in the DATE string.
  #ifndef DATE
  #ifdef __DATE__
  #define DATE __DATE__
+
+--- Lib/importlib/_bootstrap.py
++++ Lib/importlib/_bootstrap.py
+@@ -1443,7 +1443,8 @@ class SourceLoader(_LoaderBasics):
+         Implementing this method allows the loader to read bytecode files.
+         Raises IOError when the path cannot be handled.
+         """
+-        return {'mtime': self.path_mtime(path)}
++        return {'mtime': float(_os.environ.get(b'SOURCE_DATE_EPOCH',
++                                               st.st_mtime))}
+ 
+     def _cache_bytecode(self, source_path, cache_path, data):
+         """Optional method which writes data (bytes) to a file path (a str).
+@@ -1580,7 +1581,10 @@ class SourceFileLoader(FileLoader, SourceLoader):
+     def path_stats(self, path):
+         """Return the metadata for the path."""
+         st = _path_stat(path)
+-        return {'mtime': st.st_mtime, 'size': st.st_size}
++        return {
++            'mtime':  float(_os.environ.get(b'SOURCE_DATE_EPOCH', st.st_mtime)),
++            'size': st.st_size
++        }
+ 
+     def _cache_bytecode(self, source_path, bytecode_path, data):
+         # Adapt between the two APIs