diff --git a/CLAUDE.md b/CLAUDE.md
index 93847c7..16446fb 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -173,7 +173,7 @@ kernel_api 已暴露能力：log, rsdp_address, fb_address/width/height/pitch/bp
 
 下一阶段优先路线（活跃路线 = `docs/ROADMAP_INSANE.md` 五期填补计划，任务编号 F/U/D/R/E；状态唯一来源 = `docs/STATUS.md`）：
 1. **一期 F 系列收尾**: F2 统一控制台后端（fbcon.h 抽象已落，panic 已用）。（F1 莲花 panic / F3 跨平台 Makefile / F4 boot 分级自检 / F5 skip_firstinit 已完成）
-2. **二期 U 系列**: @sealed 段标记（~~U2 Slow Path~~、~~U4 密文 dump~~、~~U5 KAT~~ 已完成；chacha20 KAT 已落地为 RFC 8439 官方向量并三方对拍，"间歇 FAIL" 确认为从未合并的幽灵缺陷）。
+2. **二期 U 系列**: ✅ 已完成（U1 UUID 表 / U2 Slow Path 真分支 / U3 @sealed 可选标记+linker .sealed section / U4 密文 dump / U5 RFC 8439 KAT）。chacha20 KAT 三方对拍通过（pycryptodome+官方向量+C），"间歇 FAIL" 确认为从未合并的幽灵缺陷。
 3. **三期 D 系列**: DKM 热卸载（引用计数）、裸机器码加载器、按名 API 导出表、彩色日志。
 4. **四期 R 系列收尾**: segment/system 级回滚验证、PCQ per-cpu 多核。（~~drr_emergency_pool_kb/drr_recovery_log_size 接线~~ R3b 已完成，运行期钳位验证 PASS）
 5. **五期 E 系列**: 启动莲花动画、假想时光键彩蛋、提交信息规范、风味 ISO。
diff --git a/CODE/UTSM/include/utsm/segment.h b/CODE/UTSM/include/utsm/segment.h
index 9ba2f80..0278d65 100644
--- a/CODE/UTSM/include/utsm/segment.h
+++ b/CODE/UTSM/include/utsm/segment.h
@@ -22,6 +22,10 @@ typedef enum {
 #define UTSM_SEG_F_EXEC            (1U << 2)
 #define UTSM_SEG_F_DMA             (1U << 3)
 #define UTSM_SEG_F_STRONG_RECOVERY (1U << 4)
+/* U3: @sealed 可选标记。默认（不加此 flag）= 封缄段（密文存储，读写走 UTRW
+ * 加解密）；加 UTSM_SEG_F_UNSEALED = 明文直存段（0 加解密开销，读写仍走
+ * capability 校验与 dirty 跟踪，但直接 memcpy）。"用户能选锁不锁"。 */
+#define UTSM_SEG_F_UNSEALED        (1U << 5)
 
 typedef struct utsm_segment_desc {
     uuid128_t segment_uuid;
diff --git a/CODE/UTSM/linker.ld b/CODE/UTSM/linker.ld
index 2aede7b..677511b 100644
--- a/CODE/UTSM/linker.ld
+++ b/CODE/UTSM/linker.ld
@@ -27,6 +27,16 @@ SECTIONS
         *(COMMON)
     } :data
 
+    /* U3: @sealed 段标记 —— 用户代码可把静态数据放进 .sealed section
+     *（__attribute__((section(".sealed")))），UTSM 侧可遍历
+     * [__sealed_start, __sealed_end) 对该区建立封缄段。未标记数据 0 开销。 */
+    .sealed : ALIGN(4K) {
+        __sealed_start = .;
+        *(.sealed)
+        *(.sealed.*)
+        __sealed_end = .;
+    } :data
+
     .bss : ALIGN(4K) {
         *(.bss*)
     } :data
diff --git a/CODE/UTSM/test/utsm_selftest.c b/CODE/UTSM/test/utsm_selftest.c
index e7cdb7f..e8c81b3 100644
--- a/CODE/UTSM/test/utsm_selftest.c
+++ b/CODE/UTSM/test/utsm_selftest.c
@@ -156,6 +156,40 @@ int utsm_selftest_run(void) {
         log_info("[UTSM] selftest slow POISONED ok");
     }
 
+    /* ==== U3: @sealed 可选标记 —— unsealed 段明文直存（0 加解密开销） ==== */
+    {
+        utsm_capability ucap;
+        status = utsm_create_segment(process, UTSM_PAGE_SIZE,
+                                     UTSM_SEG_F_READ | UTSM_SEG_F_WRITE |
+                                         UTSM_SEG_F_UNSEALED,
+                                     &ucap);
+        if (status != UTSM_OK) {
+            log_error("[UTSM] selftest unsealed segment create failed");
+            return status;
+        }
+        const char *upl = "unsealed plain text 00";
+        u64 ulen = strlen(upl) + 1;
+        status = utsm_write(ucap, 128, upl, ulen);
+        if (status != UTSM_OK) {
+            log_error("[UTSM] selftest unsealed write failed");
+            return status;
+        }
+        utsm_segment_desc *udesc = utsm_get_segment(ucap.segment_slot);
+        if (!udesc) return UTSM_ERR_INVALID;
+        /* 明文直存：存储区内容必须与明文完全一致（0 开销的可观察证据） */
+        if (memcmp(udesc->cipher_base + 128, upl, ulen) != 0) {
+            log_error("[UTSM] selftest unsealed store not plaintext");
+            return UTSM_ERR_INVALID;
+        }
+        char urb[64];
+        status = utsm_read(ucap, 128, urb, ulen);
+        if (status != UTSM_OK || memcmp(urb, upl, ulen) != 0) {
+            log_error("[UTSM] selftest unsealed read failed");
+            return (status == UTSM_OK) ? UTSM_ERR_INVALID : status;
+        }
+        log_info("[UTSM] selftest unsealed segment ok (plain storage)");
+    }
+
     /* ==== SCHED-1: O(1) runqueue 语义（合成 TCB，协作式，无 tick） ==== */
     /* ==== SCHED-1 + SCHED-2: runqueue / block-wake（tick 竞态保护） ==== */
     {
diff --git a/CODE/UTSM/test/utsm_selftest.o b/CODE/UTSM/test/utsm_selftest.o
index d588f47..bde49fc 100644
Binary files a/CODE/UTSM/test/utsm_selftest.o and b/CODE/UTSM/test/utsm_selftest.o differ
diff --git a/CODE/UTSM/utrw/read.c b/CODE/UTSM/utrw/read.c
index abcac6a..3f14617 100644
--- a/CODE/UTSM/utrw/read.c
+++ b/CODE/UTSM/utrw/read.c
@@ -20,6 +20,12 @@ int utsm_read(utsm_capability cap, u64 offset, void *dst, u64 len) {
         return status;
     }
 
+    /* U3: @unsealed 段 —— 明文直存，0 加解密开销（capability 校验照走） */
+    if (desc->flags & UTSM_SEG_F_UNSEALED) {
+        memcpy(dst, desc->cipher_base + offset, len);
+        return UTSM_OK;
+    }
+
     utsm_key_material key;
     status = utsm_pckc_get_or_derive(cap.segment_slot, desc, &key);
     if (status != UTSM_OK) {
diff --git a/CODE/UTSM/utrw/read.d b/CODE/UTSM/utrw/read.d
new file mode 100644
index 0000000..c2a6c22
--- /dev/null
+++ b/CODE/UTSM/utrw/read.d
@@ -0,0 +1,14 @@
+utrw/read.o: utrw\read.c include\utsm\utrw.h include\utsm\types.h \
+  include\utsm\status.h include\utsm\capability.h include\utsm\segment.h \
+  include\utsm\uuid.h include\utsm\dirty.h include\utsm\pckc.h \
+  include\utsm\config.h include\utsm\crypto.h
+include\utsm\utrw.h:
+include\utsm\types.h:
+include\utsm\status.h:
+include\utsm\capability.h:
+include\utsm\segment.h:
+include\utsm\uuid.h:
+include\utsm\dirty.h:
+include\utsm\pckc.h:
+include\utsm\config.h:
+include\utsm\crypto.h:
diff --git a/CODE/UTSM/utrw/read.o b/CODE/UTSM/utrw/read.o
index 5f91151..b9ab9c3 100644
Binary files a/CODE/UTSM/utrw/read.o and b/CODE/UTSM/utrw/read.o differ
diff --git a/CODE/UTSM/utrw/write.c b/CODE/UTSM/utrw/write.c
index 5ddbd6f..2d04619 100644
--- a/CODE/UTSM/utrw/write.c
+++ b/CODE/UTSM/utrw/write.c
@@ -21,6 +21,18 @@ int utsm_write(utsm_capability cap, u64 offset, const void *src, u64 len) {
         return status;
     }
 
+    /* U3: @unsealed 段 —— 明文直存，0 加解密开销；dirty/seqlock/log 照走，
+     * checkpoint 路径对明文页同样适用（页 MAC 语义由 DRR 侧统一处理）。 */
+    if (desc->flags & UTSM_SEG_F_UNSEALED) {
+        drr_log_write_intent(cap.segment_slot, offset, len);
+        desc->writer_seq++;
+        memcpy(desc->cipher_base + offset, src, len);
+        utsm_mark_dirty(desc, offset, len);
+        desc->writer_seq++;
+        drr_log_write_commit(cap.segment_slot, offset, len);
+        return UTSM_OK;
+    }
+
     utsm_key_material key;
     status = utsm_pckc_get_or_derive(cap.segment_slot, desc, &key);
     if (status != UTSM_OK) {
diff --git a/CODE/UTSM/utrw/write.d b/CODE/UTSM/utrw/write.d
new file mode 100644
index 0000000..236c615
--- /dev/null
+++ b/CODE/UTSM/utrw/write.d
@@ -0,0 +1,15 @@
+utrw/write.o: utrw\write.c include\utsm\utrw.h include\utsm\types.h \
+  include\utsm\status.h include\utsm\capability.h include\utsm\segment.h \
+  include\utsm\uuid.h include\utsm\dirty.h include\utsm\pckc.h \
+  include\utsm\config.h include\utsm\crypto.h include\utsm\drr.h
+include\utsm\utrw.h:
+include\utsm\types.h:
+include\utsm\status.h:
+include\utsm\capability.h:
+include\utsm\segment.h:
+include\utsm\uuid.h:
+include\utsm\dirty.h:
+include\utsm\pckc.h:
+include\utsm\config.h:
+include\utsm\crypto.h:
+include\utsm\drr.h:
diff --git a/CODE/UTSM/utrw/write.o b/CODE/UTSM/utrw/write.o
index 1bd25a5..0bde9e8 100644
Binary files a/CODE/UTSM/utrw/write.o and b/CODE/UTSM/utrw/write.o differ
diff --git a/SYSTEM/boot/utsm.elf b/SYSTEM/boot/utsm.elf
index 73691d0..e9a9103 100755
Binary files a/SYSTEM/boot/utsm.elf and b/SYSTEM/boot/utsm.elf differ
diff --git a/SYSTEM/system/deshab64/FUCK b/SYSTEM/system/deshab64/FUCK
index 315e43c..669a173 100644
--- a/SYSTEM/system/deshab64/FUCK
+++ b/SYSTEM/system/deshab64/FUCK
@@ -99,3 +99,5 @@ pe_dll_search=1
 
 
 
+
+
diff --git a/build/configs/dev/FUCK b/build/configs/dev/FUCK
index 315e43c..669a173 100644
--- a/build/configs/dev/FUCK
+++ b/build/configs/dev/FUCK
@@ -99,3 +99,5 @@ pe_dll_search=1
 
 
 
+
+
diff --git a/docs/ROADMAP_INSANE.md b/docs/ROADMAP_INSANE.md
index 9e7e841..9817002 100644
--- a/docs/ROADMAP_INSANE.md
+++ b/docs/ROADMAP_INSANE.md
@@ -44,11 +44,11 @@ Deshab 最标志性的疯点——给空气上锁。
 |------|------|---------|------|-------------------|
 | U1 | UTSM 元数据区（UUID 表） | 每页都有"身份" | ✅ | 封缄段表 + UUID 调谐已就位（`CODE/UTSM/core/segment.c`），可查询页归属 |
 | U2 | UTRW Fast/Slow Path 真分支 | 快慢路不是画出来的 | ✅ | Fast path ✅；Slow path ✅（EPOCH/KEY_MISS 恢复，MAC_FAILED/POISONED 交 DRR，selftest PASS） |
-| U3 | `@sealed` 段可选标记 | 用户能选锁不锁 | ⬜ | 链接脚本支持 `__sealed` section；未标记段 0 开销 |
+| U3 | `@sealed` 段可选标记 | 用户能选锁不锁 | ✅ | `UTSM_SEG_F_UNSEALED` 明文直存（0 加解密开销）+ linker.ld `.sealed` section（`__sealed_start/end`）；selftest PASS |
 | U4 | 密文页 dump 工具 | 发疯也要可调试 | ✅ | `utrw_debug_dump_page`：串口 64B 密文/明文 hex 对照，selftest 内置演示（QEMU PASS） |
 | U5 | UTSM selftest 全覆盖 | 把🔶刷成✅ | ✅ | chacha20 KAT = RFC 8439 §2.4.2 官方向量（三方对拍）；"间歇 FAIL" 确认为幽灵缺陷（从未合并进树）；KAT+MAC 确定性+段表+越界+调度+DRR 全量稳定 PASS |
 
-二期做完：UTSM 从"设计"变"可开关的特性"，疯得有旋钮。
+**二期完成：UTSM 从"设计"变成"可开关的特性"，疯得有旋钮。**
 
 ---
 
diff --git a/docs/STATUS.md b/docs/STATUS.md
index 5ba7fab..264b847 100644
--- a/docs/STATUS.md
+++ b/docs/STATUS.md
@@ -27,7 +27,7 @@
 | 封缄段表 / UUID 调谐（U1） | ✅ | 段创建/查询闭环 | `CODE/UTSM/core/segment.c` |
 | UTRW Fast Path | ✅ | capability→PCKC→line 解密→seqlock | `utrw/read.c` |
 | UTRW Slow Path（U2） | ✅ | EPOCH 刷新 / KEY_MISS 重派生 / POISONED+MAC_FAILED→DRR / STALE_CAP 拒绝；全分支 selftest PASS | `utrw/slow_path.c` + `.build_tmp/qemu_serial_u2slowpath.log` |
-| `@sealed` 段标记（U3） | ⬜ | 未实现 | — |
+| `@sealed` 段标记（U3） | ✅ | 默认封缄；`UTSM_SEG_F_UNSEALED` 段明文直存（0 加解密开销，capability/dirty/checkpoint 照走）；linker.ld `.sealed` section + `__sealed_start/end` 符号就位 | `.build_tmp/qemu_serial_u3sealed.log` + llvm-nm |
 | 密文页 dump（U4） | ✅ | `utrw_debug_dump_page(slot,page,offset)`：串口输出 64B 密文/明文 hex 对照（selftest 内置演示） | `.build_tmp/qemu_serial_u4dump.log` |
 | selftest（U5） | ✅ | chacha20 KAT 落地为 RFC 8439 §2.4.2 官方向量（gen_chacha_kat.py 生成，pycryptodome 独立对拍）；"间歇 FAIL" 确认为幽灵缺陷（该测试从未合并进本树）；page MAC 确定性检查已加；全量 selftest 稳定 PASS | `.build_tmp/qemu_serial_u5kat.log` |
 | 真实加密原语 | 🔶 | chacha20/KDF/MAC 已落（Phase 9 早期），PCKC schedule 待接 | `crypto/` |
diff --git a/docs/TASKBOARD.md b/docs/TASKBOARD.md
index 00cebab..9c2ada6 100644
--- a/docs/TASKBOARD.md
+++ b/docs/TASKBOARD.md
@@ -15,7 +15,7 @@
 
 - [x] U1 UTSM 元数据区 / UUID 调谐表
 - [x] U2 UTRW Slow Path 真分支（EPOCH/KEY_MISS 恢复 + MAC_FAILED/POISONED→DRR；selftest PASS）
-- [ ] U3 `@sealed` 段可选标记（链接脚本 `__sealed` section）
+- [x] U3 `@sealed` 段可选标记（`UTSM_SEG_F_UNSEALED` 明文直存段 + linker.ld `.sealed` section；selftest PASS）
 - [x] U4 密文页 dump 工具（utrw_debug_dump_page：密文/明文 hex 对照，selftest 演示 PASS）
 - [x] U5 UTSM selftest 全覆盖（RFC 8439 KAT 落地，"间歇 FAIL" 确认为幽灵缺陷；全量稳定 PASS）