diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index cfcfa2b..578960c 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -98,6 +98,8 @@
 
 const MICRODROID_OS_NAME: &str = "microdroid";
 
+const UNFORMATTED_STORAGE_MAGIC: &str = "UNFORMATTED-STORAGE";
+
 /// Singleton service for allocating globally-unique VM resources, such as the CID, and running
 /// singleton servers, like tombstone receiver.
 #[derive(Debug, Default)]
@@ -261,6 +263,7 @@
         match partition_type {
             PartitionType::RAW => Ok(()),
             PartitionType::ANDROID_VM_INSTANCE => format_as_android_vm_instance(&mut part),
+            PartitionType::ENCRYPTEDSTORE => format_as_encryptedstore(&mut part),
             _ => Err(Error::new(
                 ErrorKind::Unsupported,
                 format!("Unsupported partition type {:?}", partition_type),
@@ -593,6 +596,11 @@
     part.flush()
 }
 
+fn format_as_encryptedstore(part: &mut dyn Write) -> std::io::Result<()> {
+    part.write_all(UNFORMATTED_STORAGE_MAGIC.as_bytes())?;
+    part.flush()
+}
+
 fn prepare_ramdump_file(ramdump_path: &Path) -> Result<File> {
     File::create(ramdump_path).context(format!("Failed to create ramdump file {:?}", &ramdump_path))
 }