diff --git a/compos/composd/src/instance_manager.rs b/compos/composd/src/instance_manager.rs
index 451222e..c3d6592 100644
--- a/compos/composd/src/instance_manager.rs
+++ b/compos/composd/src/instance_manager.rs
@@ -22,10 +22,7 @@
 use anyhow::{bail, Result};
 use binder::Strong;
 use compos_common::compos_client::VmParameters;
-use compos_common::{
-    CURRENT_INSTANCE_DIR, DEX2OAT_THREADS_PROP_NAME, PREFER_STAGED_VM_CONFIG_PATH,
-    TEST_INSTANCE_DIR,
-};
+use compos_common::{CURRENT_INSTANCE_DIR, DEX2OAT_THREADS_PROP_NAME, TEST_INSTANCE_DIR};
 use rustutils::system_properties;
 use std::num::NonZeroU32;
 use std::str::FromStr;
@@ -47,16 +44,14 @@
 
     pub fn start_current_instance(&self) -> Result<CompOsInstance> {
         let mut vm_parameters = new_vm_parameters()?;
-        vm_parameters.config_path = Some(PREFER_STAGED_VM_CONFIG_PATH.to_owned());
+        vm_parameters.prefer_staged = true;
         self.start_instance(CURRENT_INSTANCE_DIR, vm_parameters)
     }
 
     pub fn start_test_instance(&self, prefer_staged: bool) -> Result<CompOsInstance> {
         let mut vm_parameters = new_vm_parameters()?;
         vm_parameters.debug_mode = true;
-        if prefer_staged {
-            vm_parameters.config_path = Some(PREFER_STAGED_VM_CONFIG_PATH.to_owned());
-        }
+        vm_parameters.prefer_staged = prefer_staged;
         self.start_instance(TEST_INSTANCE_DIR, vm_parameters)
     }
 
diff --git a/compos/composd/src/instance_starter.rs b/compos/composd/src/instance_starter.rs
index aaa4695..fc4c58b 100644
--- a/compos/composd/src/instance_starter.rs
+++ b/compos/composd/src/instance_starter.rs
@@ -24,7 +24,10 @@
 use binder::{LazyServiceGuard, ParcelFileDescriptor, Strong};
 use compos_aidl_interface::aidl::com::android::compos::ICompOsService::ICompOsService;
 use compos_common::compos_client::{ComposClient, VmParameters};
-use compos_common::{COMPOS_DATA_ROOT, IDSIG_FILE, IDSIG_MANIFEST_APK_FILE, INSTANCE_IMAGE_FILE};
+use compos_common::{
+    COMPOS_DATA_ROOT, IDSIG_FILE, IDSIG_MANIFEST_APK_FILE, IDSIG_MANIFEST_EXT_APK_FILE,
+    INSTANCE_IMAGE_FILE,
+};
 use log::info;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -66,6 +69,7 @@
     instance_image: PathBuf,
     idsig: PathBuf,
     idsig_manifest_apk: PathBuf,
+    idsig_manifest_ext_apk: PathBuf,
     vm_parameters: VmParameters,
 }
 
@@ -76,12 +80,14 @@
         let instance_image = instance_root_path.join(INSTANCE_IMAGE_FILE);
         let idsig = instance_root_path.join(IDSIG_FILE);
         let idsig_manifest_apk = instance_root_path.join(IDSIG_MANIFEST_APK_FILE);
+        let idsig_manifest_ext_apk = instance_root_path.join(IDSIG_MANIFEST_EXT_APK_FILE);
         Self {
             instance_name: instance_name.to_owned(),
             instance_root,
             instance_image,
             idsig,
             idsig_manifest_apk,
+            idsig_manifest_ext_apk,
             vm_parameters,
         }
     }
@@ -102,6 +108,7 @@
         // Delete existing idsig files. Ignore error in case idsig doesn't exist.
         let _ = fs::remove_file(&self.idsig);
         let _ = fs::remove_file(&self.idsig_manifest_apk);
+        let _ = fs::remove_file(&self.idsig_manifest_ext_apk);
 
         let instance = self.start_vm(virtualization_service)?;
 
@@ -126,6 +133,7 @@
             instance_image,
             &self.idsig,
             &self.idsig_manifest_apk,
+            &self.idsig_manifest_ext_apk,
             &self.vm_parameters,
         )
         .context("Starting VM")?;
diff --git a/compos/composd/src/odrefresh_task.rs b/compos/composd/src/odrefresh_task.rs
index 5c926b1..a07a7f9 100644
--- a/compos/composd/src/odrefresh_task.rs
+++ b/compos/composd/src/odrefresh_task.rs
@@ -161,9 +161,18 @@
     let output_dir_raw_fd = output_dir_fd.as_raw_fd();
     let staging_dir_raw_fd = staging_dir_fd.as_raw_fd();
 
+    // Get the /system_ext FD differently because it may not exist.
+    // TODO(245761690): pass system_ext_dir_raw_fd to service.odrefresh(...)
+    let (_system_ext_dir_raw_fd, ro_dir_fds) =
+        if let Ok(system_ext_dir_fd) = open_dir(Path::new("/system_ext")) {
+            (system_ext_dir_fd.as_raw_fd(), vec![system_dir_fd, system_ext_dir_fd])
+        } else {
+            (-1, vec![system_dir_fd])
+        };
+
     // Spawn a fd_server to serve the FDs.
     let fd_server_config = FdServerConfig {
-        ro_dir_fds: vec![system_dir_fd],
+        ro_dir_fds,
         rw_dir_fds: vec![staging_dir_fd, output_dir_fd],
         ..Default::default()
     };