Beaglebone Rev A5A - Cannot connect via USB

I’m trying to connect to my Beaglebone board but it doesnt return anything. I try using the screen command on Linux/Mac and Putty(serial) on Windows and it seems to be connected but the screen keep in black. How can I debug it? The led 0 keeps blinking and the micro SD has a new Angstrom installation.

(Sorry for my english)

The board does not boot from the uSD. It boots from the eMMC. You need to remove the uSD and let the board boot from the eMMC.