diff --git a/attachment_s3/models/ir_attachment.py b/attachment_s3/models/ir_attachment.py
index 1c8a060..b03b511 100644
--- a/attachment_s3/models/ir_attachment.py
+++ b/attachment_s3/models/ir_attachment.py
@@ -178,10 +178,35 @@ class IrAttachment(models.Model):
         else:
             return super(IrAttachment, self)._store_file_read(fname, bin_size)
 
+
+    def _inverse_datas(self):
+        location = self._storage()
+        for attach in self:
+            # compute the fields that depend on datas
+            value = attach.datas
+            bin_data = base64.b64decode(value) if value else b''
+            vals = {
+                'file_size': len(bin_data),
+                'checksum': self._compute_checksum(bin_data),
+                'index_content': self._index(bin_data, attach.datas_fname, attach.mimetype),
+                'store_fname': False,
+                'db_datas': value,
+            }
+            if value and location != 'db':
+                # save it to the filestore
+                vals['store_fname'] = self._file_write(value, vals['checksum'], mimetype=attach.mimetype)
+                vals['db_datas'] = False
+
+            # take current location in filestore to possibly garbage-collect it
+            fname = attach.store_fname
+            # write as superuser, as user probably does not have write access
+            super(IrAttachment, attach.sudo()).write(vals)
+            if fname:
+                self._file_delete(fname)
+
     @api.model
-    def _store_file_write(self, key, bin_data):
+    def _store_file_write(self, key, bin_data, mimetype=False):
         location = self.env.context.get('storage_location') or self._storage()
-        mimetype = self.env.context.get('mimetype') or self.mimetype
         if location == 's3':
             bucket = self._get_s3_bucket()
             obj = bucket.Object(key=key)
diff --git a/base_attachment_object_storage/models/ir_attachment.py b/base_attachment_object_storage/models/ir_attachment.py
index 1ef2a8a..0a3ecfa 100644
--- a/base_attachment_object_storage/models/ir_attachment.py
+++ b/base_attachment_object_storage/models/ir_attachment.py
@@ -164,10 +164,6 @@ class IrAttachment(models.Model):
                 return len(bin_data) <= limit
         return False
 
-    def _get_datas_related_values(self, data, mimetype):
-        self=self.with_context(mimetype=mimetype)
-        return super(IrAttachment, self)._get_datas_related_values(data, mimetype)
-
     def _inverse_datas(self):
         # override in order to store files that need fast access,
         # we keep them in the database instead of the object storage