I have some problems about building my own uboot

[SW C]

Dear all,

   I try to build uboot and want to boot-up from SD card. I have several questions.

1.Could I use the /origin/master branch  in git://git.denx.de/u-boot.git ?

2.Currently, my latest code is commit 73b6e6ad25 which the commit date is Nov. 4 2019

   Could I use the config file /configs/am335x_boneblack_vboot_defconfig?

I use the setting as above to generate MLO and u-boot.img, but it seems the boot-up from SD card is fail. BBB connects to my windows laptop via USB cable.  I just see the COM port is showed in my laptop and disappeared again repeatedly. I don't know why? Does anyone have any suggestion? Thanks a lot. 

BR,

Eddie

[Robert Nelson]

For any u-boot work, you need a real usb-serial adapter plugged into
J1, to monitor u-boot booting, otherwise you'll just waste your own
time..

https://elinux.org/Beagleboard:BeagleBone_Black_Serial

Regards,

--
Robert Nelson
https://rcn-ee.com/