diff --git a/__pycache__/backend.cpython-39.pyc b/__pycache__/backend.cpython-39.pyc
index 3da93ce..2319b42 100644
Binary files a/__pycache__/backend.cpython-39.pyc and b/__pycache__/backend.cpython-39.pyc differ
diff --git a/backend.py b/backend.py
index 4dae880..6fe8d39 100644
--- a/backend.py
+++ b/backend.py
@@ -978,9 +978,49 @@ def _auto_install_grub(mount_point: str, distro_type: str) -> bool:
         timeout=300
     )
     
+    # 即使 yum 报告"已安装"，也要检查实际命令是否存在
+    # CentOS/RHEL 的命令可能在 /usr/sbin/ 下，需要确保 PATH 包含该路径
     if success:
-        log_success(f"✓ GRUB 包安装成功")
-        return True
+        log_info("包安装命令执行完成，检查命令是否可用...")
+        
+        # 尝试查找 grub 相关命令的实际路径
+        grub_paths = [
+            "/usr/sbin/grub2-install",
+            "/usr/sbin/grub2-mkconfig", 
+            "/usr/sbin/grub-install",
+            "/usr/sbin/grub-mkconfig",
+            "/sbin/grub2-install",
+            "/sbin/grub2-mkconfig",
+        ]
+        
+        found_any = False
+        for grub_path in grub_paths:
+            full_path = mount_point + grub_path
+            if os.path.exists(full_path):
+                log_info(f"  找到 GRUB 命令: {grub_path}")
+                found_any = True
+        
+        if found_any:
+            log_success(f"✓ GRUB 包已安装")
+            return True
+        else:
+            log_warning("包管理器报告成功，但未找到 GRUB 命令")
+            log_info("尝试重新安装...")
+            
+            # 强制重新安装
+            if distro_type in ["centos", "rhel", "fedora", "rocky", "almalinux"]:
+                reinstall_cmd = chroot_cmd_prefix + ["yum", "reinstall", "-y"] + packages
+                run_command(reinstall_cmd, "强制重新安装 GRUB 包", timeout=300)
+            
+            # 再次检查
+            for grub_path in grub_paths:
+                full_path = mount_point + grub_path
+                if os.path.exists(full_path):
+                    log_info(f"  找到 GRUB 命令: {grub_path}")
+                    return True
+            
+            log_error("仍无法找到 GRUB 命令")
+            return False
     else:
         log_error(f"✗ GRUB 包安装失败: {stderr}")
         return False
@@ -994,7 +1034,7 @@ def check_chroot_environment(mount_point: str, distro_type: str = "unknown") ->
     """
     log_step("检查 chroot 环境", f"挂载点: {mount_point}")
     
-    # 检查关键命令是否存在
+    # 检查关键命令是否存在（在 PATH 中）
     critical_commands = ["grub-install", "grub-mkconfig", "update-grub", "grub2-install", "grub2-mkconfig"]
     found_commands = []
     
@@ -1007,6 +1047,25 @@ def check_chroot_environment(mount_point: str, distro_type: str = "unknown") ->
         else:
             log_debug(f"  ✗ 未找到命令: {cmd}")
     
+    # 如果在 PATH 中未找到，检查常见的sbin路径（某些发行版sbin不在默认PATH中）
+    if not found_commands:
+        log_info("在 PATH 中未找到命令，检查 sbin 目录...")
+        sbin_paths = [
+            "/usr/sbin/grub2-install",
+            "/usr/sbin/grub2-mkconfig",
+            "/usr/sbin/grub-install",
+            "/usr/sbin/grub-mkconfig",
+            "/sbin/grub2-install",
+            "/sbin/grub2-mkconfig",
+        ]
+        
+        for sbin_path in sbin_paths:
+            full_path = mount_point + sbin_path
+            if os.path.exists(full_path):
+                cmd_name = os.path.basename(sbin_path)
+                found_commands.append(cmd_name)
+                log_info(f"  ✓ 找到命令: {sbin_path}")
+    
     if not found_commands:
         log_warning(f"chroot 环境中未找到关键的 GRUB 命令")
         log_info(f"尝试自动安装 GRUB 包...")