diff --git a/src/a2a3/platform/onboard/host/device_runner.cpp b/src/a2a3/platform/onboard/host/device_runner.cpp
index 3f99e5d61..484196b8c 100644
--- a/src/a2a3/platform/onboard/host/device_runner.cpp
+++ b/src/a2a3/platform/onboard/host/device_runner.cpp
@@ -432,6 +432,24 @@ int DeviceRunner::run(Runtime &runtime, const CallConfig &config) {
         l2_swimlane_collector_.set_core_types(core_types.data(), num_aicore);
     }
 
+    rc = launch_run(runtime, num_aicore, launch_aicpu_num);
+    if (rc != 0) return rc;
+
+    rc = reap_run();
+    if (rc != 0) return rc;
+
+    // Print handshake results (reads from device memory, must be before free)
+    print_handshake_results();
+
+    return 0;
+}
+
+int DeviceRunner::launch_run(Runtime &runtime, int num_aicore, int launch_aicpu_num) {
+    // KernelLaunch is the pipeline boundary: this method clears the handshake
+    // consumed by the launch and submits exactly the AICore and AICPU kernels.
+    // It intentionally performs no stream synchronization or per-run cleanup.
+    int rc = 0;
+
     // Launch the AICore worker BEFORE the AICPU Run task — mirrors the a5 path
     // so the two arches stay symmetric. First-launch latency optimization +
     // op-timeout-family defense-in-depth: with the AICPU Run task launched first
@@ -478,7 +496,11 @@ int DeviceRunner::run(Runtime &runtime, const CallConfig &config) {
         return rc;
     }
 
-    rc = sync_run_streams();
+    return 0;
+}
+
+int DeviceRunner::reap_run() {
+    int rc = sync_run_streams();
     if (rc != 0) {
         // sync_run_streams surfaces the AICore op-timeout (STARS-reaped op ->
         // 507000/507018/507046 at AICPU/AICore stream sync). The op-timeout
@@ -517,9 +539,6 @@ int DeviceRunner::run(Runtime &runtime, const CallConfig &config) {
         }
     }
 
-    // Print handshake results (reads from device memory, must be before free)
-    print_handshake_results();
-
     return 0;
 }
 
diff --git a/src/a2a3/platform/onboard/host/device_runner.h b/src/a2a3/platform/onboard/host/device_runner.h
index 62904e293..f5a2231d8 100644
--- a/src/a2a3/platform/onboard/host/device_runner.h
+++ b/src/a2a3/platform/onboard/host/device_runner.h
@@ -97,8 +97,8 @@ class DeviceRunner : public DeviceRunnerBase {
      * 1. Initializes device if not already done (lazy initialization)
      * 2. Initializes worker handshake buffers in the runtime based on block_dim
      * 3. Transfers runtime to device memory
-     * 4. Launches AICPU main kernel
-     * 5. Launches AICore kernel
+     * 4. Launches AICore kernel
+     * 5. Launches AICPU main kernel
      * 6. Synchronizes streams
      * 7. Cleans up runtime memory
      *
@@ -219,6 +219,11 @@ class DeviceRunner : public DeviceRunnerBase {
     // recovery. See run() and recover_device_or_mark_unusable().
     bool device_unusable_{false};
 
+    // Keep the kernel submission boundary separate from stream synchronization
+    // and teardown. run() still invokes these back-to-back in this change.
+    int launch_run(Runtime &runtime, int num_aicore, int launch_aicpu_num);
+    int reap_run();
+
     // On an AICore launch/sync error, best-effort drain the device so a later
     // run() on the same DeviceRunner can recover in place; if the drain itself
     // errors the context is unrecoverable without a full reset, so flip