Use the RCA cable that it came with, then set your tv to that RCA setting then once you plug in your Box hit the menu button right away and set the Video to NTSC toi 1080i then scroll down to save settings or something like that then with the right arrow button it will give you the option to save it and from there it will reboot and you can now go into the HDMI settings as it should boot up normally
I believe you have to be in the BIOS screen to get to those vid settings, PAL or ATSC...I could be wrong
once in it's an F key will change it back and forth but can't remember which one, sorry