I got NanoPi Duo board and I want use SPI flash for boot limited Linux. I soldered W25Q64 SPI flash chip, it's detected as mtd device if I use SD card for boot.
But I can't find information how to build image for download to SPI flash. I read article http://linux-sunxi.org/Bootable_SPI_flash, but it's not sufficient for build OS image.
Can you recommend manual for build this image?

Thanks in advance.