diff --git a/src/ipc/ipc-common.c b/src/ipc/ipc-common.c
index d05895a3f13a..831ba9e8d47d 100644
--- a/src/ipc/ipc-common.c
+++ b/src/ipc/ipc-common.c
@@ -437,15 +437,6 @@ int ipc_user_forward_cmd(uint32_t primary, uint32_t extension, unsigned int core
 	pdata->ipc_msg_ext = extension;
 	pdata->ipc = ipc;
 
-	/*
-	 * Forwarding the first IPC to this core, wait for its userspace IPC
-	 * thread to start
-	 */
-	if (pdata->init_needed[core]) {
-		pdata->init_needed[core] = false;
-		k_sem_take(pdata->sem, K_FOREVER);
-	}
-
 	/* Prevent host completion until user thread finishes */
 	key = k_spin_lock(&ipc->lock);
 	ipc->task_mask |= IPC_TASK_IN_THREAD;
@@ -598,9 +589,6 @@ __cold int ipc_user_init_secondary(unsigned int core)
 	}
 
 	k_thread_access_grant(ipc_user->thread[core], ipc_user->audio_thread[core]);
-	ipc_user->init_needed[core] = true;
-
-	/* Wait for user thread startup — consumes the initial k_sem_give from thread */
 	return 0;
 }
 
@@ -619,7 +607,7 @@ __cold static void ipc_user_init(void)
 	struct ipc_user *ipc_user = sof_heap_alloc(sof_sys_user_heap_get(),
 						   SOF_MEM_FLAG_USER | SOF_MEM_FLAG_COHERENT,
 						   sizeof(*ipc_user), 0);
-	int ret;
+	int ret, core;
 
 	if (!ipc_user) {
 		LOG_ERR("user IPC pdata alloc failed");
@@ -628,6 +616,11 @@ __cold static void ipc_user_init(void)
 
 	assert_can_be_cold();
 
+	for (core = 0; core < CONFIG_CORE_COUNT; core++) {
+		if (core != PLATFORM_PRIMARY_CORE_ID)
+			ipc_user->init_needed[core] = true;
+	}
+
 	ipc_user->sem = k_object_alloc(K_OBJ_SEM);
 	if (!ipc_user->sem) {
 		LOG_ERR("user IPC sem alloc failed");
diff --git a/src/ipc/ipc4/handler-kernel.c b/src/ipc/ipc4/handler-kernel.c
index 03c2e6c81e86..041b0fba14f2 100644
--- a/src/ipc/ipc4/handler-kernel.c
+++ b/src/ipc/ipc4/handler-kernel.c
@@ -328,6 +328,23 @@ __cold static int ipc4_module_process_d0ix(struct ipc4_message_request *ipc4)
 	return 0;
 }
 
+/* block until core has powered-up (in user-ll builds) */
+__cold static void ipc_sec_core_sync_boot(uint32_t core_id)
+{
+#ifdef CONFIG_SOF_USERSPACE_LL
+	struct ipc *ipc = ipc_get();
+	struct ipc_user *ipc_user = ipc->ipc_user_pdata;
+
+	assert(core_id != PLATFORM_PRIMARY_CORE_ID);
+
+	if (ipc_user->init_needed[core_id]) {
+		/* wait for IPC thread (ipc_user_thread_fn()) */
+		k_sem_take(ipc_user->sem, K_FOREVER);
+		ipc_user->init_needed[core_id] = false;
+	}
+#endif
+}
+
 /* enable/disable cores according to the state mask */
 __cold static int ipc4_module_process_dx(struct ipc4_message_request *ipc4)
 {
@@ -385,6 +402,7 @@ __cold static int ipc4_module_process_dx(struct ipc4_message_request *ipc4)
 				ipc_cmd_err(&ipc_tr, "failed to enable core %d", core_id);
 				return IPC4_FAILURE;
 			}
+			ipc_sec_core_sync_boot(core_id);
 		} else {
 			cpu_disable_core(core_id);
 			if (cpu_is_core_enabled(core_id)) {