diff --git a/rust/agama-lib/src/dbus.rs b/rust/agama-lib/src/dbus.rs
index b814f614b6..50383f7b6b 100644
--- a/rust/agama-lib/src/dbus.rs
+++ b/rust/agama-lib/src/dbus.rs
@@ -29,6 +29,8 @@ where
     T::try_from(value).map_err(|e| e.into())
 }
 
+/// It is similar helper like get_property with difference that name does not need to be in HashMap.
+/// In such case `None``is returned, so type has to be enclosed in `Option`.`
 pub fn get_optional_property<'a, T>(
     properties: &'a HashMap<String, OwnedValue>,
     name: &str,
diff --git a/rust/agama-lib/src/error.rs b/rust/agama-lib/src/error.rs
index 5ef274afe3..30f61af834 100644
--- a/rust/agama-lib/src/error.rs
+++ b/rust/agama-lib/src/error.rs
@@ -10,6 +10,8 @@ pub enum ServiceError {
     DBus(#[from] zbus::Error),
     #[error("Could not connect to Agama bus at '{0}': {1}")]
     DBusConnectionError(String, #[source] zbus::Error),
+    #[error("D-Bus protocol error: {0}")]
+    DBusProtocol(#[from] zbus::fdo::Error),
     #[error("Unexpected type on D-Bus '{0}'")]
     ZVariant(#[from] zvariant::Error),
     // it's fine to say only "Error" because the original
diff --git a/rust/agama-lib/src/storage/client.rs b/rust/agama-lib/src/storage/client.rs
index 3c49b2866c..3828c02720 100644
--- a/rust/agama-lib/src/storage/client.rs
+++ b/rust/agama-lib/src/storage/client.rs
@@ -32,6 +32,7 @@ pub struct Action {
 }
 
 /// Represents value for target key of Volume
+/// It is snake cased when serializing to be compatible with yast2-storage-ng.
 #[derive(Debug, Clone, Serialize, Deserialize, utoipa::ToSchema)]
 #[serde(rename_all = "snake_case")]
 pub enum VolumeTarget {
@@ -286,7 +287,7 @@ impl<'a> StorageClient<'a> {
     ) -> Result<Device, ServiceError> {
         let interfaces = &object.1;
         Ok(Device {
-            device_info: self.build_device_info(interfaces).await?,
+            device_info: self.build_device_info(object).await?,
             component: None,
             drive: None,
             block_device: self.build_block_device(interfaces).await?,
@@ -302,11 +303,7 @@ impl<'a> StorageClient<'a> {
     }
 
     pub async fn system_devices(&self) -> Result<Vec<Device>, ServiceError> {
-        let objects = self
-            .object_manager_proxy
-            .get_managed_objects()
-            .await
-            .context("Failed to get managed objects")?;
+        let objects = self.object_manager_proxy.get_managed_objects().await?;
         let mut result = vec![];
         for object in objects {
             let path = &object.0;
@@ -321,11 +318,7 @@ impl<'a> StorageClient<'a> {
     }
 
     pub async fn staging_devices(&self) -> Result<Vec<Device>, ServiceError> {
-        let objects = self
-            .object_manager_proxy
-            .get_managed_objects()
-            .await
-            .context("Failed to get managed objects")?;
+        let objects = self.object_manager_proxy.get_managed_objects().await?;
         let mut result = vec![];
         for object in objects {
             let path = &object.0;
@@ -341,8 +334,12 @@ impl<'a> StorageClient<'a> {
 
     async fn build_device_info(
         &self,
-        interfaces: &HashMap<OwnedInterfaceName, HashMap<std::string::String, OwnedValue>>,
+        object: &(
+            OwnedObjectPath,
+            HashMap<OwnedInterfaceName, HashMap<std::string::String, OwnedValue>>,
+        ),
     ) -> Result<DeviceInfo, ServiceError> {
+        let interfaces = &object.1;
         let interface: OwnedInterfaceName =
             InterfaceName::from_static_str_unchecked("org.opensuse.Agama.Storage1.Device").into();
         let properties = interfaces.get(&interface);
@@ -354,9 +351,9 @@ impl<'a> StorageClient<'a> {
                 description: get_property(properties, "Description")?,
             })
         } else {
-            Err(ServiceError::Anyhow(anyhow!(
-                "Device does not implement device info"
-            )))
+            let message =
+                format!("storage device {} is missing Device interface", object.0).to_string();
+            Err(zbus::zvariant::Error::Message(message).into())
         }
     }