No HDMI output

Howdy. I have n interesting problem where I can boot and get HDMI output from my DE10 Nano with the SD card that comes with it, but when I build up an SD card (I've tried 2) the green activity light blinks like it's booting up, but I never see anything on the screen. Again, 2 SD cards (one I've formatted 3x) and no bueno, but the SD card that comes with the Nano does boot. I haven't tried connecting to the serial port to see what's going on (successful boot or error messages). That's the next step I guess unless one of you have ran into this before. If you have, please share how you fixed it. Thanks!