diff --git a/libs/libavf/src/lib.rs b/libs/libavf/src/lib.rs
index 256803f..50c5e2e 100644
--- a/libs/libavf/src/lib.rs
+++ b/libs/libavf/src/lib.rs
@@ -19,7 +19,6 @@
 use std::os::fd::{FromRawFd, IntoRawFd};
 use std::os::raw::{c_char, c_int};
 use std::ptr;
-use std::sync::Arc;
 use std::time::Duration;
 
 use android_system_virtualizationservice::{
@@ -30,10 +29,10 @@
     },
     binder::{ParcelFileDescriptor, Strong},
 };
-use avf_bindgen::{AVirtualMachineStopReason, AVirtualMachine_stopCallback};
+use avf_bindgen::AVirtualMachineStopReason;
 use libc::timespec;
 use log::error;
-use vmclient::{DeathReason, ErrorCode, VirtualizationService, VmCallback, VmInstance};
+use vmclient::{DeathReason, VirtualizationService, VmInstance};
 
 /// Create a new virtual machine config object with no properties.
 #[no_mangle]
@@ -343,49 +342,6 @@
     }
 }
 
-struct LocalVmInstance {
-    vm: Arc<VmInstance>,
-    callback: AVirtualMachine_stopCallback,
-}
-
-impl VmCallback for LocalVmInstance {
-    fn on_payload_started(&self, _cid: i32) {
-        // Microdroid only. no-op.
-    }
-
-    fn on_payload_ready(&self, _cid: i32) {
-        // Microdroid only. no-op.
-    }
-
-    fn on_payload_finished(&self, _cid: i32, _exit_code: i32) {
-        // Microdroid only. no-op.
-    }
-
-    fn on_error(&self, _cid: i32, _error_code: ErrorCode, _message: &str) {
-        // Microdroid only. no-op.
-    }
-
-    fn on_died(&self, _cid: i32, death_reason: DeathReason) {
-        let Some(callback) = self.callback else {
-            return;
-        };
-        let stop_reason = death_reason_to_stop_reason(death_reason);
-        let vm_ptr: *const VmInstance = Arc::into_raw(Arc::clone(&self.vm));
-
-        // SAFETY: `callback` is assumed to be a valid, non-null function pointer passed by
-        // `AVirtualMachine_start`.
-        unsafe {
-            callback(vm_ptr.cast(), stop_reason);
-        }
-
-        // drop ptr after use.
-        // SAFETY: `vm_ptr` is a valid, non-null pointer casted above.
-        unsafe {
-            let _ = Arc::from_raw(vm_ptr);
-        }
-    }
-}
-
 /// Create a virtual machine with given `config`.
 ///
 /// # Safety
@@ -401,7 +357,7 @@
     console_out_fd: c_int,
     console_in_fd: c_int,
     log_fd: c_int,
-    vm_ptr: *mut *const VmInstance,
+    vm_ptr: *mut *mut VmInstance,
 ) -> c_int {
     // SAFETY: `service` is assumed to be a valid, non-null pointer returned by
     // `AVirtualizationService_create` or `AVirtualizationService_create_early`. It's the only
@@ -420,8 +376,9 @@
     match VmInstance::create(service.as_ref(), &config, console_out, console_in, log, None) {
         Ok(vm) => {
             // SAFETY: `vm_ptr` is assumed to be a valid, non-null pointer to a mutable raw pointer.
+            // `vm` is the only reference here and `vm_ptr` takes ownership.
             unsafe {
-                *vm_ptr = Arc::into_raw(Arc::new(vm));
+                *vm_ptr = Box::into_raw(Box::new(vm));
             }
             0
         }
@@ -437,20 +394,11 @@
 /// # Safety
 /// `vm` must be a pointer returned by `AVirtualMachine_createRaw`.
 #[no_mangle]
-pub unsafe extern "C" fn AVirtualMachine_start(
-    vm: *const VmInstance,
-    callback: AVirtualMachine_stopCallback,
-) -> c_int {
+pub unsafe extern "C" fn AVirtualMachine_start(vm: *const VmInstance) -> c_int {
     // SAFETY: `vm` is assumed to be a valid, non-null pointer returned by
     // `AVirtualMachine_createRaw`. It's the only reference to the object.
-    let vm = unsafe { Arc::from_raw(vm) };
-    let callback = callback.map(|_| {
-        let cb: Box<dyn VmCallback + Send + Sync> =
-            Box::new(LocalVmInstance { vm: Arc::clone(&vm), callback });
-        cb
-    });
-
-    match vm.start(callback) {
+    let vm = unsafe { &*vm };
+    match vm.start(None) {
         Ok(_) => 0,
         Err(e) => {
             error!("AVirtualMachine_start failed: {e:?}");
@@ -561,12 +509,12 @@
 /// `vm` must be a pointer returned by `AVirtualMachine_createRaw`. `vm` must not be reused after
 /// deletion.
 #[no_mangle]
-pub unsafe extern "C" fn AVirtualMachine_destroy(vm: *const VmInstance) {
+pub unsafe extern "C" fn AVirtualMachine_destroy(vm: *mut VmInstance) {
     if !vm.is_null() {
         // SAFETY: `vm` is assumed to be a valid, non-null pointer returned by
         // AVirtualMachine_create. It's the only reference to the object.
         unsafe {
-            let _ = Arc::from_raw(vm);
+            let _ = Box::from_raw(vm);
         }
     }
 }