diff --git a/android/compos_verify/verify.rs b/android/compos_verify/verify.rs
index b94ebbc..a3f18d5 100644
--- a/android/compos_verify/verify.rs
+++ b/android/compos_verify/verify.rs
@@ -124,7 +124,6 @@
         &idsig_manifest_ext_apk,
         &VmParameters {
             name: String::from("ComposVerify"),
-            os: String::from("microdroid"),
             cpu_topology: VmCpuTopology::OneCpu, // This VM runs very little work at boot
             debug_mode: args.debug,
             ..Default::default()
diff --git a/android/composd/aidl/android/system/composd/IIsolatedCompilationService.aidl b/android/composd/aidl/android/system/composd/IIsolatedCompilationService.aidl
index 3748899..dde75e1 100644
--- a/android/composd/aidl/android/system/composd/IIsolatedCompilationService.aidl
+++ b/android/composd/aidl/android/system/composd/IIsolatedCompilationService.aidl
@@ -48,6 +48,5 @@
      * callback, unless the returned ICompilationTask is cancelled. The caller should maintain
      * a reference to the ICompilationTask until compilation completes or is cancelled.
      */
-    ICompilationTask startTestCompile(
-            ApexSource apexSource, ICompilationTaskCallback callback, String os);
+    ICompilationTask startTestCompile(ApexSource apexSource, ICompilationTaskCallback callback);
 }
diff --git a/android/composd/src/instance_manager.rs b/android/composd/src/instance_manager.rs
index cb1f7e4..9e94035 100644
--- a/android/composd/src/instance_manager.rs
+++ b/android/composd/src/instance_manager.rs
@@ -46,12 +46,11 @@
         self.start_instance(CURRENT_INSTANCE_DIR, vm_parameters)
     }
 
-    pub fn start_test_instance(&self, prefer_staged: bool, os: &str) -> Result<CompOsInstance> {
+    pub fn start_test_instance(&self, prefer_staged: bool) -> Result<CompOsInstance> {
         let mut vm_parameters = new_vm_parameters()?;
         vm_parameters.name = String::from("ComposdTest");
         vm_parameters.debug_mode = true;
         vm_parameters.prefer_staged = prefer_staged;
-        vm_parameters.os = os.to_owned();
         self.start_instance(TEST_INSTANCE_DIR, vm_parameters)
     }
 
diff --git a/android/composd/src/service.rs b/android/composd/src/service.rs
index 3cc40af..49cfd3a 100644
--- a/android/composd/src/service.rs
+++ b/android/composd/src/service.rs
@@ -60,7 +60,6 @@
         &self,
         apex_source: ApexSource,
         callback: &Strong<dyn ICompilationTaskCallback>,
-        os: &str,
     ) -> binder::Result<Strong<dyn ICompilationTask>> {
         check_permissions()?;
         let prefer_staged = match apex_source {
@@ -68,7 +67,7 @@
             ApexSource::PreferStaged => true,
             _ => unreachable!("Invalid ApexSource {:?}", apex_source),
         };
-        to_binder_result(self.do_start_test_compile(prefer_staged, callback, os))
+        to_binder_result(self.do_start_test_compile(prefer_staged, callback))
     }
 }
 
@@ -94,12 +93,9 @@
         &self,
         prefer_staged: bool,
         callback: &Strong<dyn ICompilationTaskCallback>,
-        os: &str,
     ) -> Result<Strong<dyn ICompilationTask>> {
-        let comp_os = self
-            .instance_manager
-            .start_test_instance(prefer_staged, os)
-            .context("Starting CompOS")?;
+        let comp_os =
+            self.instance_manager.start_test_instance(prefer_staged).context("Starting CompOS")?;
 
         let target_dir_name = TEST_ARTIFACTS_SUBDIR.to_owned();
         let task = OdrefreshTask::start(
diff --git a/android/composd_cmd/composd_cmd.rs b/android/composd_cmd/composd_cmd.rs
index 6281bd0..6d096a1 100644
--- a/android/composd_cmd/composd_cmd.rs
+++ b/android/composd_cmd/composd_cmd.rs
@@ -46,10 +46,6 @@
         /// If any APEX is staged, prefer the staged version.
         #[clap(long)]
         prefer_staged: bool,
-
-        /// OS for the VM.
-        #[clap(long, default_value = "microdroid")]
-        os: String,
     },
 }
 
@@ -60,7 +56,7 @@
 
     match action {
         Actions::StagedApexCompile {} => run_staged_apex_compile()?,
-        Actions::TestCompile { prefer_staged, os } => run_test_compile(prefer_staged, &os)?,
+        Actions::TestCompile { prefer_staged } => run_test_compile(prefer_staged)?,
     }
 
     println!("All Ok!");
@@ -120,9 +116,9 @@
     run_async_compilation(|service, callback| service.startStagedApexCompile(callback))
 }
 
-fn run_test_compile(prefer_staged: bool, os: &str) -> Result<()> {
+fn run_test_compile(prefer_staged: bool) -> Result<()> {
     let apex_source = if prefer_staged { ApexSource::PreferStaged } else { ApexSource::NoStaged };
-    run_async_compilation(|service, callback| service.startTestCompile(apex_source, callback, os))
+    run_async_compilation(|service, callback| service.startTestCompile(apex_source, callback))
 }
 
 fn run_async_compilation<F>(start_compile_fn: F) -> Result<()>
diff --git a/libs/libcompos_common/compos_client.rs b/libs/libcompos_common/compos_client.rs
index 6872582..316eaa9 100644
--- a/libs/libcompos_common/compos_client.rs
+++ b/libs/libcompos_common/compos_client.rs
@@ -58,8 +58,6 @@
 pub struct VmParameters {
     /// The name of VM for identifying.
     pub name: String,
-    /// The OS of VM.
-    pub os: String,
     /// Whether the VM should be debuggable.
     pub debug_mode: bool,
     /// CPU topology of the VM. Defaults to 1 vCPU.
@@ -131,7 +129,6 @@
 
         let config = VirtualMachineConfig::AppConfig(VirtualMachineAppConfig {
             name: parameters.name.clone(),
-            osName: parameters.os.clone(),
             apk: Some(apk_fd),
             idsig: Some(idsig_fd),
             instanceId: instance_id,