装系统吗？
先下载一个系统镜像，格式为img/iso
打开终端，dd装载
df -h # show which is SD card
> /dev/disk2s1 252Mi 53Mi 199Mi 22% 0 0 100% /Volumes/boot
diskutil umountDisk /dev/disk2 # unmount operation
sudo su
dd bs=1m if=/path/to/image/raspbian-buster-lite.img of=/dev/rdisk2