diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/loop_uart_proto.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/loop_uart_proto.c
index 0f0941b..3c999d2 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/loop_uart_proto.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/loop_uart_proto.c
@@ -686,12 +686,16 @@ void lup_process_frame(const uint8_t *pkg, uint16_t len)
 
     if (len < 6) { FAULT_MARKER(MK_LUP_FRAME_OUT); return; }
 
-    // Debug: print raw
-    PRINT("LUP Rx:");
-    for (i = 0; i < len; i++) {
-        PRINT(" %02X", pkg[i]);
+    // Debug: print raw (2026-08-13: 缓冲一次性输出 — 逐字节 PRINT 关中断 ~350us/字节
+    // 会屏蔽 UART2 ISR 丢帧, 且高频打印放大 printf 重入窗口)
+    {
+        char _hex[224];
+        int _p = snprintf(_hex, sizeof(_hex), "LUP Rx:");
+        for (i = 0; i < len && _p >= 0 && _p < (int)sizeof(_hex) - 5; i++) {
+            _p += snprintf(_hex + _p, sizeof(_hex) - (size_t)_p, " %02X", pkg[i]);
+        }
+        PRINT("%s\n", _hex);
     }
-    PRINT("\n");
 
     // --- Checksum ---
     csr = lup_verify_checksum(pkg, len);
diff --git a/vd960DBN/SRC/Debug/debug.h b/vd960DBN/SRC/Debug/debug.h
index ebead36..ca8e7bd 100644
--- a/vd960DBN/SRC/Debug/debug.h
+++ b/vd960DBN/SRC/Debug/debug.h
@@ -46,7 +46,16 @@ void USART_Printf_Init(uint32_t baudrate);
 void SDI_Printf_Enable(void);
 
 #if(DEBUG)
-  #define PRINT(format, ...)    printf(format, ##__VA_ARGS__)
+  /* 2026-08-13 printf 重入修复: BLE 协议栈回调(peripheral.c, BB 中断上下文)
+     与主循环都有 PRINT, 交叉调用 printf → 输出乱码 + 堆/状态破坏 → HardFault。
+     临界区用保存/恢复 MSTATUS: 中断里调用也能正确恢复, 不会嵌套误开中断。
+     注意: 高频逐字节 PRINT (如 LUP Rx hex) 会长时间关中断, 应改缓冲一次性输出 */
+  #define PRINT(format, ...) do { \
+      uint32_t _print_ms = __get_MSTATUS(); \
+      __disable_irq(); \
+      printf(format, ##__VA_ARGS__); \
+      __set_MSTATUS(_print_ms); \
+  } while(0)
 #else
   #define PRINT(X...)
 #endif