Mag 254 Bios
1 unplug Mag254
2 push and hold the button with 3 dots and 3 lines and plug power back in you should have a blue screen with settings.
3 Check and change your setting save and reboot

Things you may need to change
1 Video settings should be set to your TV settings
2 You should be booting from nand or nand 2 which ever that works for you.
3 Factory Reset. ( Screen shows def. setting )