Please, check the troubleshooting section: https://github.com/avafinger/bpi-m64-firmware#troublehooting
This symptoms is typically described when you have a bad SD CARD.
Please, get another SD card, 16GB preferable , find a good and trusted brand and start over following instructions verbatim.
And make sure you:
- DON'T use DVI to HDMI
- HAVE a 1080P60 TV/Monitor capable, this image will not boot in 720P
- Read https://github.com/avafinger/bpi-m64-firmware#troublehooting and https://github.com/avafinger/bpi-m64-firmware#before-you-start-downloading-and-flashing-you-should-pay-attention-to-this