I fixed my problem using the latest Clover r2652 and  from @hack.in regarding ntfs.efi.

In my particular case (with uefi installed Windows 7), I mistakenly omitted EFI as the Default Boot Volume (I only entered bootmgfw.efi as Default Loader).

To fix the problem, you need to

Place ntfs.efi in EFI/CLOVER/drivers64 or drivers64UEFI

Delete your current NVRAM settings...in terminal

sudo rm /nvram.plist sudo nvram -c

Edit your config.plist, entering the Default Boot Volume and ticking IgnoreNVRAMBoot with Clover Configurator...

With the correct config.plist settings, everything works as expected (including timeout countdown!)....

Of course for legacy Windows, the Default Boot Volume would usually be "system reserved"

总结

Clover配置文件config.plist里的<DefaultVolume>和<DefaultLoader>是配合起感化的：<DefaultVolume>指定默认的启动分区，这里我们设置为EFI分区的GUID；<DefaultLoader>指定默认分区中的启动文件，这里因为我们默认的EFI分区里只有一个WIN10 EFI MANAGER（Clover被我放在另一个硬盘的EFI分区里了），所以不设置该项，Clover可以自动找到启动文件。

设置<IgnoreNVRAMBoot>为<true>，这里不太懂，，但这对象或存在BUG或成果缺掉。所以必需在 EFI/CLOVER/drivers64UEFI 文件夹下放入文件 NTFS.efi