BeagleBone Black serial peripheral boot:
BBB supports many peripheral boot options which can be choosen by the SYSBOOT button projected out near p8 header.
Button pressed the sequence is spi0 | mmc0 | usb0 | uart0
Button released the sequence is mmc1 | mmc0 | uart0 | usb0
so we have uart0 in both the sequence. We go for the sequence when button is pressed.
Here ROM code accepts the xmodem protocol for receiving the binary file so in Linux we have sx command for that.
$ sx -vvv <bin file> < <device file> > <device file>