diff --git a/patch_v2/meow_audiod/meow_audiod b/patch_v2/meow_audiod/meow_audiod
index 1f1d049..b64d658 100755
Binary files a/patch_v2/meow_audiod/meow_audiod and b/patch_v2/meow_audiod/meow_audiod differ
diff --git a/patch_v2/meow_audiod/meow_audiod.c b/patch_v2/meow_audiod/meow_audiod.c
index 561e7d0..20da178 100644
--- a/patch_v2/meow_audiod/meow_audiod.c
+++ b/patch_v2/meow_audiod/meow_audiod.c
@@ -405,6 +405,8 @@ static const char *port_name(int port)
     switch (port) {
     case 2: return "3.5 headset";
     case 3: return "4.4 balance";
+    case 4: return "i2s/spdif digital";
+    case 5: return "none(disable)";
     default: return "idle";
     }
 }
@@ -1121,6 +1123,21 @@ static void *route_thread(void *arg)
     (void)arg;
     int last_hb = -1, last_bal = -1, last_target = -1;
     logmsg("route thread init (numid=9, %s)", g_amixer);
+    /* M2.91 挂死根治（AUDIO_HANG_INVESTIGATION.md）：hbc3000 FPGA 未烧录+enable 时
+     * 启动 PCM 会在第二次 hbc3000_start 死锁整机。写 Output Port Switch 是烧录触发器
+     * （驱动 put：set_spdif_mode→program_ram→enabled）。开机端口恒 0=未烧，故启动时
+     * 无条件写一次：4.4 在→3，3.5 在→2，都没→4（官方播放器拔插孔后的选择，保 FPGA 已烧）。
+     * 端口已是目标值（audiod 重启场景，驱动同值短路不写）→ 先写 5(disable) 强制重烧。 */
+    {
+        int hb = read_switch("/sys/class/switch/headset/state");
+        int bal = read_switch("/sys/class/switch/balance/state");
+        int target = (bal == 1) ? 3 : (hb == 1) ? 2 : 4;
+        int cur = amixer_get(9, 1);
+        if (cur == target) { logmsg("route: port already %d, force re-arm via 5", target); apply_route(5); }
+        apply_route(target);
+        last_hb = hb; last_bal = bal; last_target = (hb == 0 && bal == 0) ? -1 : target;
+        logmsg("route: boot arm done (port %d %s, FPGA programmed)", target, port_name(target));
+    }
     while (!g_stop) {
         pthread_mutex_lock(&g_mu);
         route_evaluate(&last_hb, &last_bal, &last_target);