hi3531DV200设置从emmc启动，uboot重启后只打印一次空格，uboot没有启动，为什么？

hi3531DV200设置从emmc启动，uboot重启后调试串口只打印一次空格，uboot没有启动，为什么？

HITOOL 工具（HiTool-BVT-5.3.7）界面串口打印的信息：

串口已经连接，请给单板上电，若已经上电，请断电后重新上电。
######################### ---- 10%
######################## ---- 20%
######################## ---- 30%
######################## ---- 40%
######################## ---- 51%
######################## ---- 61%
######################## ---- 71%
######################## ---- 81%
######################## ---- 91%
################### ---- 100%
Boot download completed!
     

System startup

Uncompress.............Ok


U-Boot 2016.11 (May 16 2020 - 11:19:59 +0800)hi3531dv200

Relocation Offset is: 1775d000
Relocating to 5ff5d000, new gd at 5febce20, sp at 5febce10
MMC:   mmc->ocr_from_bootrom 0x00000000
sdhci-hisi: tuning done! valid phase shift [18, 13] Final Phase:31
** First descriptor is NOT a primary desc on 0:1 **
MMC/SD Card:
    MID:         0x15
    Read Block:  512 Bytes
    Write Block: 512 Bytes
    Chip Size:   7456M Bytes (High Capacity)
    Name:        "8GTF4"
    Chip Type:   MMC
    Version:     5.1
    Speed:       148500000Hz
    Bus Width:   4bit
    Mode:        HS200
hisi-sdhci: 0 (eMMC)
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   gmac0
Error: gmac0 address not set.

start download process.

Boot started successfully!

Send command:        mmc write 0x0 0x41000000 0x0 0x19a

MMC write: dev # 0, block # 0, count 410 ... 410 blocks written: OK
[EOT](OK)
Fastboot burnt successfully!

Send command:        reset
reset success!


上电重启，
uboot重启后调试串口只打印一次空格，uboot没有启动，为什么？