Write card from img file:dd bs=4m if=xxxx-xxxx-raspbian.img of=/dev/xxx
Card replacement/expansion/backup: enter the system, insert a new card or a new card transferred by a card reader, umount /media/xxx
and then sudo dd bs=4M if=/dev/mmcblk0 of=/dev/sda(maybe sdb sdc...) there is
no prompt in the copy process, wait for the
copy to be completed Start with a new card and use the expansion space in the sudo raspi-config tool
Copying a high-capacity card to a low-capacity card should not work