1. Please check the format of your microSD card, Please format the card to exFAT/FAT32 and set "Allocation unit size" to 32KB/64KB. please refer to:
Which type of microSD card is fit for RunCam Split?
2. The pins of the SD card slot may not be in the right place. And it leads to the bad connection of the SD card. Refer to the following video to solve the problem, please：