diff --git a/stactools_sentinel2/stactools/sentinel2/stac.py b/stactools_sentinel2/stactools/sentinel2/stac.py
index a99223b8..1b211484 100644
--- a/stactools_sentinel2/stactools/sentinel2/stac.py
+++ b/stactools_sentinel2/stactools/sentinel2/stac.py
@@ -116,8 +116,9 @@ def create_item(
         for image_path in product_metadata.image_paths
     ])
 
-    for asset in image_assets.items():
-        item.add_asset(*asset)
+    for key, asset in image_assets.items():
+        assert key not in item.assets
+        item.add_asset(key, asset)
 
     # Thumbnail
 
@@ -205,7 +206,7 @@ def set_asset_properties(asset):
                              roles=['data'])
         item.ext.eo.set_bands([SENTINEL_BANDS[band_id]], asset)
         set_asset_properties(asset)
-        return (asset_href[-7:].replace('_', '-'), asset)
+        return (band_id, asset)
 
     # Handle auxiliary images
 
diff --git a/tests/sentinel2/test_commands.py b/tests/sentinel2/test_commands.py
index 396df1d9..45d312a9 100644
--- a/tests/sentinel2/test_commands.py
+++ b/tests/sentinel2/test_commands.py
@@ -7,6 +7,7 @@
 
 from stactools.core.projection import reproject_geom
 from stactools.sentinel2.commands import create_sentinel2_command
+from stactools.sentinel2.constants import SENTINEL_BANDS
 from tests.utils import (TestData, CliTestCase)
 
 
@@ -56,7 +57,15 @@ def check_proj_bbox(item):
 
                         item.validate()
 
+                        bands_seen = set()
+
                         for asset in item.assets.values():
                             self.assertTrue(is_absolute_href(asset.href))
+                            bands = item.ext.eo.get_bands(asset)
+                            if bands is not None:
+                                bands_seen |= set(b.name for b in bands)
+
+                        self.assertEqual(bands_seen,
+                                         set(SENTINEL_BANDS.keys()))
 
                         check_proj_bbox(item)