Other Parts Discussed in Thread: AM4378,
I was trying to load u-boot using JATG for the AM4378 custom board by referring the following URL.
http://processors.wiki.ti.com/index.php/Sitara_Linux_Training:_uboot_linux_debug_with_ccsv5
In the above link it was explained that setting break point in s_init function at board.c under "board/ti/am335x/".
I couldn't find s_init for AM4376 for setting the break point. I was using ubuntu 2016.