diff --git a/requirements-swh.txt b/requirements-swh.txt
--- a/requirements-swh.txt
+++ b/requirements-swh.txt
@@ -1,5 +1,5 @@
 swh.core >= 0.3
-swh.model >= 1.0.0
+swh.model >= 3.1.0
 swh.objstorage >= 0.2.2
 swh.scheduler >= 0.4.0
 swh.storage >= 0.29.0
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
@@ -37,15 +37,14 @@
 class DebianFileMetadata:
     name = attr.ib(type=str)
     """Filename"""
-    sha256 = attr.ib(type=str)
+
     size = attr.ib(type=int)
     uri = attr.ib(type=str)
     """URL of this specific file"""
 
-    # md5sum is not always available, make it optional
+    # all checksums are not always available, make them optional
+    sha256 = attr.ib(type=str, default="")
     md5sum = attr.ib(type=str, default="")
-
-    # sha1 is not always available, make it optional
     sha1 = attr.ib(type=str, default="")
 
     # Some of the DSC files imported in swh apparently had a Checksums-SHA512
@@ -307,9 +306,13 @@
     for filename, fileinfo in p_info.files.items():
         uri = fileinfo.uri
         logger.debug("fileinfo: %s", fileinfo)
-        extrinsic_hashes = {"sha256": fileinfo.sha256}
+        extrinsic_hashes = {"md5": fileinfo.md5sum}
+        if fileinfo.sha256:
+            extrinsic_hashes["sha256"] = fileinfo.sha256
+        if fileinfo.sha1:
+            extrinsic_hashes["sha1"] = fileinfo.sha1
         logger.debug("extrinsic_hashes(%s): %s", filename, extrinsic_hashes)
-        filepath, hashes = download(
+        _, hashes = download(
             uri, dest=tmpdir, filename=filename, hashes=extrinsic_hashes
         )
         all_hashes[filename] = hashes
diff --git a/swh/loader/package/debian/tests/test_debian.py b/swh/loader/package/debian/tests/test_debian.py
--- a/swh/loader/package/debian/tests/test_debian.py
+++ b/swh/loader/package/debian/tests/test_debian.py
@@ -287,6 +287,7 @@
     assert all_hashes == {
         "cicero_0.7.2-3.diff.gz": {
             "checksums": {
+                "md5": "a93661b6a48db48d59ba7d26796fc9ce",
                 "sha1": "0815282053f21601b0ec4adf7a8fe47eace3c0bc",
                 "sha256": "f039c9642fe15c75bed5254315e2a29f9f2700da0e29d9b0729b3ffc46c8971c",  # noqa
             },
@@ -299,6 +300,7 @@
         },
         "cicero_0.7.2-3.dsc": {
             "checksums": {
+                "md5": "d5dac83eb9cfc9bb52a15eb618b4670a",
                 "sha1": "abbec4e8efbbc80278236e1dd136831eac08accd",
                 "sha256": "35b7f1048010c67adfd8d70e4961aefd8800eb9a83a4d1cc68088da0009d9a03",  # noqa
             },
@@ -310,6 +312,7 @@
         },
         "cicero_0.7.2.orig.tar.gz": {
             "checksums": {
+                "md5": "4353dede07c5728319ba7f5595a7230a",
                 "sha1": "a286efd63fe2c9c9f7bb30255c3d6fcdcf390b43",
                 "sha256": "63f40f2436ea9f67b44e2d4bd669dbabe90e2635a204526c20e0b3c8ee957786",  # noqa
             },
@@ -476,3 +479,44 @@
     )
 
     check_snapshot(expected_snapshot, swh_storage)
+
+
+def test_debian_loader_only_md5_sum_in_dsc(swh_storage, requests_mock_datadir):
+
+    packages_per_version = deepcopy(PACKAGES_PER_VERSION)
+    for package_files in packages_per_version.values():
+        for package_data in package_files["files"].values():
+            del package_data["sha256"]
+
+    loader = DebianLoader(swh_storage, URL, packages=packages_per_version)
+
+    actual_load_status = loader.load()
+    expected_snapshot_id = "a83fa5c089b048161f0677b9614a4aae96a6ca18"
+    assert actual_load_status == {
+        "status": "eventful",
+        "snapshot_id": expected_snapshot_id,
+    }
+
+    assert_last_visit_matches(
+        swh_storage,
+        URL,
+        status="full",
+        type="deb",
+        snapshot=hash_to_bytes(expected_snapshot_id),
+    )
+
+    expected_snapshot = Snapshot(
+        id=hash_to_bytes(expected_snapshot_id),
+        branches={
+            b"releases/stretch/contrib/0.7.2-3": SnapshotBranch(
+                target_type=TargetType.RELEASE,
+                target=hash_to_bytes("73e0ede9c21f7074ad1f9c81a774cfcb9e02addf"),
+            ),
+            b"releases/buster/contrib/0.7.2-4": SnapshotBranch(
+                target_type=TargetType.RELEASE,
+                target=hash_to_bytes("9f6d8d868514f991af0d9f5d7173aba1236a5a75"),
+            ),
+        },
+    )
+
+    check_snapshot(expected_snapshot, swh_storage)
diff --git a/swh/loader/package/tests/test_utils.py b/swh/loader/package/tests/test_utils.py
--- a/swh/loader/package/tests/test_utils.py
+++ b/swh/loader/package/tests/test_utils.py
@@ -39,7 +39,7 @@
 _data = "this is something"
 
 
-def _check_download_ok(url, dest, filename=_filename, hashes=None):
+def _check_download_ok(url, dest, filename=_filename, hashes={}):
     actual_filepath, actual_hashes = download(url, dest, hashes=hashes)
 
     actual_filename = os.path.basename(actual_filepath)
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
@@ -124,7 +124,7 @@
     filepath = os.path.join(dest, filename)
     logger.debug("filepath: %s", filepath)
 
-    h = MultiHash(hash_names=DOWNLOAD_HASHES)
+    h = MultiHash(hash_names=DOWNLOAD_HASHES | set(hashes.keys()))
     with open(filepath, "wb") as f:
         for chunk in response_data:
             h.update(chunk)