AM6442: AM 6442 系统烧录启动问题

  HELLO: 

  There is a problem with the system burning of AM6442and its startup. The BOOT is set to start from the SD card, and the burning is done through the SD card. However, when powered on, there is no print information on serial port 0. All hardware power supplies are normal (the core voltage uses 0.75 VDD_CORE). DDR4 and EMMC are the DDR4 (MT40A512M16LY-107E) and 8GB EMMC that have been used on the customer's development board. The 25M crystal oscillator is used for oscillation. There is no print on the serial port. Could you please tell me what conditions need to be met for AM6411 to be able to boot from the SD card? ！ Are there any relevant documents for reference? thank you!

       AM6411 系统烧录问题及启动，BOOT设置成SD卡启动，通过SD卡烧录，上电串口0没有任何打印信息，硬件所有供电正常（内核电压使用得0.75 VDD_CORE），DDR4，EMMC是在客户开发板上使用过得 DDR4（MT40A512M16LY-107E）和8GB EMMC ，25M晶体起振，串口0（D15，C16）没有任何打印，请问有AM6411能从SD烧录启动需要满足什么条件？有相关文档介绍没？谢谢！