diff --git a/swh/loader/package/debian/loader.py b/swh/loader/package/debian/loader.py
--- a/swh/loader/package/debian/loader.py
+++ b/swh/loader/package/debian/loader.py
@@ -259,7 +259,8 @@
         extrinsic_hashes = {'sha256': fileinfo['sha256']}
         logger.debug('extrinsic_hashes(%s): %s', filename, extrinsic_hashes)
         filepath, hashes = download(uri, dest=tmpdir, filename=filename,
-                                    hashes=extrinsic_hashes)
+                                    hashes=extrinsic_hashes,
+                                    on_length_error_raise=False)
         all_hashes[filename] = hashes
 
     logger.debug('all_hashes: %s', all_hashes)
diff --git a/swh/loader/package/utils.py b/swh/loader/package/utils.py
--- a/swh/loader/package/utils.py
+++ b/swh/loader/package/utils.py
@@ -40,7 +40,8 @@
 
 def download(url: str, dest: str, hashes: Dict = {},
              filename: Optional[str] = None,
-             auth: Optional[Tuple[str, str]] = None) -> Tuple[str, Dict]:
+             auth: Optional[Tuple[str, str]] = None,
+             on_length_error_raise: bool = True) -> Tuple[str, Dict]:
     """Download a remote tarball from url, uncompresses and computes swh hashes
        on it.
 
@@ -51,6 +52,10 @@
             to download (those hashes are expected to be hex string)
         auth: Optional tuple of login/password (for http authentication
             service, e.g. deposit)
+        on_length_error_raise: If true, when length described and actual
+        downloaded length diverge, raise (default behavior). Otherwise, this
+        will try to continue download (can only be true if hashes to check are
+        provided)
 
     Raises:
         ValueError in case of any error when fetching/computing (length,
@@ -60,6 +65,9 @@
         Tuple of local (filepath, hashes of filepath)
 
     """
+    # accept to bypass error on length check only when hashes are provided
+    assert on_length_error_raise or (not on_length_error_raise and hashes)
+
     params = copy.deepcopy(DEFAULT_PARAMS)
     if auth is not None:
         params['auth'] = auth
@@ -85,8 +93,12 @@
 
     actual_length = os.path.getsize(filepath)
     if length != actual_length:
-        raise ValueError('Error when checking size: %s != %s' % (
-            length, actual_length))
+        msg = f'Error when checking size: {length} != {actual_length}'
+        if on_length_error_raise:
+            raise ValueError(msg)
+        else:
+            logger.warning('%s. Continue assuming erroneous data upstream',
+                           msg)
 
     # Also check the expected hashes if provided
     if hashes: