如何自制ULINK2,或者手动给ULINK2升级,可以参考这篇文章,这篇文章详细介绍了如何降级,说简单点就是把里面单片机数据擦除了再重新写你想要的版本-How homemade ULINK2, or manually to ULINK2 upgrade, you can refer to this article, this article details how to downgrade, that simple point is to erase the data inside the chip and then re-write the version you want,