Sir,
I am also facing the same issue of HDMI port. The sample_video.avi does not produce any output on LCD monitor. I have used Beagle_Revc4_Validation.img and followed the same procedure as mentioned by Mr. Kishore Kumar Boddu for bootargs and bootcmd but even though I am not getting output on Monitor and also not able to bring the board in network through USB to ethernet converter.
I am using Beagle Board Rev C3 board.