Methods for updating and recovering user data of a non-volatile memory array such as a flash memory are disclosed. An indication for indicating a mapping relationship for a logical address is established when original user data of the logical addresses is updated into new user data. The indication records new pointers, which record the mapping relationships between logical addresses and physical addresses storing the new user data of the logical addresses. Alternatively, the indication records memory positions of the non-volatile memory array which are defined as designated memory positions and a sequence for using these designated memory positions.