8192 MiB
MMC:   SUNXI SD/MMC: 0
*** Warning - bad CRC, using default environment

Reserved 8192kB of RAM for Framebuffer.
In:    serial
Out:   serial
Err:   serial
Net:   dwmac.1c50000
Unknown command 'usb' - try 'help'
Hit any key to stop autoboot:  0
sun7i# nand unlock boot0
device 0 offset 0x0, size 0x200000
sunxi_nfc_cmd_ctrl dat is: 0x70
and ctrl is 0x83
sunxi_nfc_cmd_ctrl dat is: 0xffffffff
and ctrl is 0x81
nand_unlock: Device is write protected!
70
Error unlocking NAND flash, write and erase will probably fail
sun7i#