diff --git a/swh/loader/package/archive/tests/data/not_gzipped_tarball.tar.gz b/swh/loader/package/archive/tests/data/not_gzipped_tarball.tar.gz
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
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literal 0
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diff --git a/swh/loader/package/archive/tests/test_archive.py b/swh/loader/package/archive/tests/test_archive.py
--- a/swh/loader/package/archive/tests/test_archive.py
+++ b/swh/loader/package/archive/tests/test_archive.py
@@ -4,10 +4,13 @@
 # See top-level LICENSE file for more information
 
 import hashlib
+from io import BytesIO
+from pathlib import Path
 import string
 
 import attr
 import pytest
+from requests.exceptions import ContentDecodingError
 
 from swh.loader.package.archive.loader import ArchiveLoader, ArchivePackageInfo
 from swh.loader.tests import assert_last_visit_matches, check_snapshot, get_stats
@@ -416,3 +419,47 @@
     branch_target_second_visit = snapshot.branches[branch_artifact1_name].target
 
     assert branch_target_first_visit != branch_target_second_visit
+
+
+@pytest.fixture
+def not_gzipped_tarball_bytes(datadir):
+    return Path(datadir, "not_gzipped_tarball.tar.gz").read_bytes()
+
+
+def test_archive_not_gzipped_tarball(
+    swh_storage, requests_mock, not_gzipped_tarball_bytes
+):
+    """Check that a tarball erroneously marked as gzip compressed can still
+    be downloaded and processed.
+
+    """
+    filename = "not_gzipped_tarball.tar.gz"
+    url = f"https://example.org/ftp/{filename}"
+    requests_mock.get(
+        url,
+        [
+            {"exc": ContentDecodingError,},
+            {"body": BytesIO(not_gzipped_tarball_bytes),},
+        ],
+    )
+    loader = ArchiveLoader(
+        swh_storage,
+        url,
+        artifacts=[
+            {
+                "time": 944729610,
+                "url": url,
+                "length": 221837,
+                "filename": filename,
+                "version": "0.1.0",
+            }
+        ],
+    )
+
+    actual_load_status = loader.load()
+    assert actual_load_status["status"] == "eventful"
+    assert actual_load_status["snapshot_id"] is not None
+
+    snapshot = loader.last_snapshot()
+    assert len(snapshot.branches) == 2
+    assert b"releases/0.1.0" in snapshot.branches
diff --git a/swh/loader/package/loader.py b/swh/loader/package/loader.py
--- a/swh/loader/package/loader.py
+++ b/swh/loader/package/loader.py
@@ -28,6 +28,7 @@
 )
 
 import attr
+from requests.exceptions import ContentDecodingError
 import sentry_sdk
 
 from swh.core.tarball import uncompress
@@ -361,7 +362,20 @@
             List of (path, computed hashes)
 
         """
-        return [download(p_info.url, dest=tmpdir, filename=p_info.filename)]
+        try:
+            return [download(p_info.url, dest=tmpdir, filename=p_info.filename)]
+        except ContentDecodingError:
+            # package might be erroneously marked as gzip compressed while is is not,
+            # try to download its raw bytes again without attempting to uncompress
+            # the input stream
+            return [
+                download(
+                    p_info.url,
+                    dest=tmpdir,
+                    filename=p_info.filename,
+                    extra_request_headers={"Accept-Encoding": "identity"},
+                )
+            ]
 
     def uncompress(
         self, dl_artifacts: List[Tuple[str, Mapping[str, Any]]], dest: str
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
@@ -51,6 +51,7 @@
     hashes: Dict = {},
     filename: Optional[str] = None,
     auth: Optional[Tuple[str, str]] = None,
+    extra_request_headers: Optional[Dict[str, str]] = None,
 ) -> Tuple[str, Dict]:
     """Download a remote tarball from url, uncompresses and computes swh hashes
        on it.
@@ -74,6 +75,8 @@
     params = copy.deepcopy(DEFAULT_PARAMS)
     if auth is not None:
         params["auth"] = auth
+    if extra_request_headers is not None:
+        params["headers"].update(extra_request_headers)
     # so the connection does not hang indefinitely (read/connection timeout)
     timeout = params.get("timeout", 60)
     response = requests.get(url, **params, timeout=timeout, stream=True)