我们参考TI官方demo板做了一块AM4379的核心板

ARM MPU AM437X Starter Kit EVM

配置从SD卡启动后，串口打印信息如下：

U-Boot SPL 2016.05-g2f757e5b2c (Oct 03 2016 - 18:09:21)
Trying to boot from MMC1
omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
SPL: Please implement spl_start_uboot() for your board
SPL: Direct Linux boot not active!
** Partition 1 not valid on device 0 **
spl_register_fat_device: fat register err - -1
spl_load_image_fat: error reading image u-boot.img, err - -1
SPL: Please implement spl_start_uboot() for your board
SPL: Direct Linux boot not active!
spl: no partition table found
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

请问这是什么问题？