diff --git a/VKernel/Kernel/main.vp b/VKernel/Kernel/main.vp
index fa1d02b..08b389c 100644
--- a/VKernel/Kernel/main.vp
+++ b/VKernel/Kernel/main.vp
@@ -34,6 +34,31 @@ import asm
 kbd_tid: int = -1
 mse_tid: int = -1
 
+# 影子副本 + 校验：__init__ 的 fb/width/height/pitch 局部量曾被偶发写坏（被清零，
+# 导致 desktop.start 拿到 fb=0 → 刷新把后备缓冲写到物理 0 起，覆盖内核自身）。
+# 这里保存模块级影子并在关键节点比对，命中即 fail-fast 暴露写坏源，不再让损坏值被静默使用。
+_ShadowFb: uint64 = 0
+_ShadowW: int = 0
+_ShadowH: int = 0
+_ShadowPitch: int = 0
+
+def _SetFrameShadow(fb: rawptr, w: int, h: int, pitch: int):
+    global _ShadowFb, _ShadowW, _ShadowH, _ShadowPitch
+    _ShadowFb = uint64(fb)
+    _ShadowW = w
+    _ShadowH = h
+    _ShadowPitch = pitch
+
+def _CheckFrameLocals(tag: const str, fb: rawptr, w: int, h: int, pitch: int):
+    if uint64(fb) != _ShadowFb or w != _ShadowW or h != _ShadowH or pitch != _ShadowPitch:
+        b: [176]char
+        viperlib.snprintf(&b, 176,
+            "[FATAL] %s: frame locals corrupted fb=0x%lx w=%d h=%d pitch=%d (expect 0x%lx %d %d %d)\n",
+            tag, uint64(fb), w, h, pitch, _ShadowFb, _ShadowW, _ShadowH, _ShadowPitch)
+        serial.puts(&b)
+        while True:
+            sched.Scheduler._yield()
+
 BootInfo: bootinfo.bootinfo*
 
 class ViperKernel:
@@ -128,6 +153,7 @@ class ViperKernel:
         pitch:     int = int(BootInfo.framebuffer_pitch)
         fb_format: int = int(BootInfo.framebuffer_format)
         fb_size:   uint64 = BootInfo.framebuffer_size
+        _SetFrameShadow(fb, width, height, pitch)
         # [DBG] 打印 BootInfo 指针与 memmap 原始字段，定位全 0 根因（用后移除）
         _dbbuf: [140]char
         viperlib.snprintf(&_dbbuf, 140, "[main] BootInfo=0x%lx mmap=0x%lx mmsz=%lu mmd=%lu fb=0x%lx\n",
@@ -292,6 +318,7 @@ class ViperKernel:
         # paging and mm already initialized before FAT32
 
         usb.init()
+        _CheckFrameLocals("after_usb", fb, width, height, pitch)
 
         serial.puts("[main] starting keyboard service\n")
         kbd_svc.start()
@@ -302,9 +329,11 @@ class ViperKernel:
         VGA_drv = vga._VGAScreenDriver(fb, width, height, pitch, fb_format)
         self.VGA = &VGA_drv
         self.VGA.Print(100, 100, "ViperOS VKernel Test")
+        _CheckFrameLocals("after_vga", fb, width, height, pitch)
         serial.puts("你好\n")
 
         serial.puts("[main] starting desktop\n")
+        _CheckFrameLocals("pre_desktop", fb, width, height, pitch)
         desktop.start(fb, width, height, pitch)
         serial.puts("[main] desktop started\n")