手上有一批CH554E，同一个编带取下来的芯片，有几颗焊到PCB上，是能通过USB正常烧录程序的。大部分插到USB上都是不识别没反应的。我反复做过各种实验，确定是芯片问题。不能识别的PCB，换了正常的芯片后，就可以正常识别烧录了，由此可以判断出PCB、外围电路是没有问题的。严重怀疑有问题的芯片是内部没有bootloader。求指点，应该怎样才能烧录bootloader?

您好，我们公司生产的芯片是一定会内置BOOT程序的。您认为没有BOOT的主要依据是什么？或者购买信息是什么？详细情况可以与技术沟通：025-52635387

纯属推测，要不我把芯片寄给你试试，如果是假货，我去投诉卖家。如果是漏烧BOOTLOADER的，烧好寄回给我。这样你们也可以了解一下，市场上是否有以假乱真的情况。我确认芯片外围电路没有问题。芯片是真是假还是没有BOOTLOADER就不得而知。

您好，建议您可以留个联系电话或者联系我司的客户经理025-52638388进行配合处理，谢谢！

Well i must say we had the same problem with some chips from ali express, They could not start the bootloader. We have tried both bootpins as well as serial boot. Nothing worked.

Since i dont believe that the chips are without loader i guess somehow the bootloader got deactivated.

There is an option for that in config space.

This just happens with a few chips from ALi. Batches from LCSC were always fine. So we did not investigate further. I think this may happen more often now since LCSC has no stock.