I also have completed this method.
I have c:\wiiu.brick.img 31 268 536 320 bytes
Made Win32DiskImager.
I have tried execute:
sdio_nand_manager
and open c:\wiiu.brick.img
but i have got this error:
"NAND dump signature is not matchinge commnad"
NAND Extractor also does not open
Somebody help...