RunCam HD just blinks yellow after powering on, then blinks faster for a few secs, then off. What's the problem?

According to the description, it's because the SD card is not be recognized normally. Pls try the methods below:
1.Do not use 64G SD card.
2.The SD card is not compatible or broken, pls try another one.
3.The SD card is not standard fat32 or exFAT form, pls use PC to format.
4.Check the card slot to see if it's broken.