nand flash 16 read data isn't equal write data

I use OMAPL137_flashandbootutil_2_40 to transfer data to MT29F2G16ABA flash,but what I write isn't equal read, if the write data is that 0xAA 0xBB 0xCC 0xDD 0xEE 0xFF 0xGG 0xHH 0xPP 0xMM 0xNN and so on, but I read data are that 0xAA 0x00 0xCC 0x00 0xEE 0x00 0xGG 0x00 0xPP 0x00 0xNN and so on ,I use buswidth16. could you help me?