diff --git a/test/host/run_boot_test.py b/test/host/run_boot_test.py
index 399d33a7..6aa53131 100644
--- a/test/host/run_boot_test.py
+++ b/test/host/run_boot_test.py
@@ -51,7 +51,9 @@ from datetime import datetime
 from pathlib import Path
 
 SCRIPT_DIR = Path(__file__).resolve().parent
-REPO_ROOT = SCRIPT_DIR.parent
+# 本脚本位于 test/host/，仓库根需上溯两级（2026-10 实机窗口修：原 .parent 只到 test/，
+# 导致 .opencode/serial_config.json 与 tools/serial_tool 路径解析错误）
+REPO_ROOT = SCRIPT_DIR.parent.parent
 SERIAL_TOOL = REPO_ROOT / "tools" / "serial_tool" / "serial_tool.py"
 CFG_FILE = REPO_ROOT / ".opencode" / "serial_config.json"
 DEFAULT_FLASH = REPO_ROOT / "MDK-ARM" / "download.bat"