diff --git a/encryptedstore/README.md b/encryptedstore/README.md
index 544d6eb..3d55d85 100644
--- a/encryptedstore/README.md
+++ b/encryptedstore/README.md
@@ -5,7 +5,7 @@
 Any data written in encrypted storage is persisted and is available next time the VM is run.
 
 Encrypted Storage is backed by a para-virtualized block device on the guest which is further
-backed by a qcow2 disk image in the host. The block device is formatted with an ext4 filesystem.
+backed by a disk image file in the host. The block device is formatted with an ext4 filesystem.
 
 ## Security
 
diff --git a/virtualizationmanager/src/aidl.rs b/virtualizationmanager/src/aidl.rs
index 0c4aa7c..28d47a4 100644
--- a/virtualizationmanager/src/aidl.rs
+++ b/virtualizationmanager/src/aidl.rs
@@ -67,7 +67,6 @@
     IntoBinderResult,
 };
 use cstr::cstr;
-use disk::QcowFile;
 use glob::glob;
 use lazy_static::lazy_static;
 use log::{debug, error, info, warn};
@@ -256,15 +255,17 @@
             .context("failed to move cursor to start")
             .or_service_specific_exception(-1)?;
         image.set_len(0).context("Failed to reset a file").or_service_specific_exception(-1)?;
-
-        let mut part = QcowFile::new(image, size_bytes)
-            .context("Failed to create QCOW2 image")
+        // Set the file length. In most filesystems, this will not allocate any physical disk
+        // space, it will only change the logical size.
+        image
+            .set_len(size_bytes)
+            .context("Failed to extend file")
             .or_service_specific_exception(-1)?;
 
         match partition_type {
             PartitionType::RAW => Ok(()),
-            PartitionType::ANDROID_VM_INSTANCE => format_as_android_vm_instance(&mut part),
-            PartitionType::ENCRYPTEDSTORE => format_as_encryptedstore(&mut part),
+            PartitionType::ANDROID_VM_INSTANCE => format_as_android_vm_instance(&mut image),
+            PartitionType::ENCRYPTEDSTORE => format_as_encryptedstore(&mut image),
             _ => Err(Error::new(
                 ErrorKind::Unsupported,
                 format!("Unsupported partition type {:?}", partition_type),