Sinovoip BananaPi BPI-R4 update Wiki?

Oh if I understand correctly I should flash the same image to nand (the openwrt-mediatek-filogic-bananapi_bpi-r4-sdcard.img ).
Right ?
From banana-pi's Wiki I tried without success.

mtd erase /dev/mtd0
Could not open mtd device: /dev/mtd0
Could not open mtd device: /dev/mtd0

Could anyone tell me how to to it (if possible without needing a serial console) ?
Thank you very much.