Flashing SPI NAND

Once you have a working system on the board (either the bootstrap image or a previously flashed firmware), you can write a fresh bootloader and rootfs to the SPI NAND.

For a fresh board, the bootstrap flow (./bootstrap.sh or the make bootstrap-bundle .run) runs every step below automatically over SSH. The manual procedure here is kept as reference and for one-off re-flashes.

On the host: copy artifacts to the board

After make build MACHINE=network_player, the relevant output files live in out/network_player/:

spi-nand.bin — mknandboot.sh-processed u-boot-with-spl.bin, ready for mtd0
rootfs.ubifs — UBIFS image for the rootfs volume

Copy them to the running system, using the data partition as scratch:

scp -O out/network_player/rootfs.ubifs root@192.168.2.2:/mnt/data
scp -O out/network_player/spi-nand.bin root@192.168.2.2:/mnt/data

(Make sure /mnt/data is mounted from ubi2_0 — see FOTA strategy for the one-time UBI setup.)

On the board: erase, format, write

If this is the very first time you touch the NAND from Linux, erase the raw MTD partitions:

flash_erase /dev/mtd0 0 0
flash_erase /dev/mtd1 0 0
flash_erase /dev/mtd2 0 0
flash_erase /dev/mtd3 0 0

Then format the UBI partitions:

ubiformat /dev/mtd1
ubiformat /dev/mtd2
ubiformat /dev/mtd3

Attach and create volumes (one-time setup, see FOTA strategy):

ubiattach -p /dev/mtd1
ubiattach -p /dev/mtd2
ubiattach -p /dev/mtd3
ubimkvol /dev/ubi0 -N fota   -m
ubimkvol /dev/ubi1 -N rootfs -m
ubimkvol /dev/ubi2 -N data   -m

Finally, do the actual writes:

# Bootloader: raw write into mtd0
flashcp /mnt/data/spi-nand.bin /dev/mtd0

# Rootfs: applied to UBI volume ubi1_0
ubiupdatevol /dev/ubi1_0 /mnt/data/rootfs.ubifs

Reboot — the board should now come up from NAND with the new firmware.

Alternative: flashing from U-Boot

For the very first flash (no usable Linux on the device yet), the bootloader can be written from U-Boot itself, after loading it into RAM through FEL:

sunxi-fel -p uboot images/u-boot-sunxi-with-spl.bin \
  write 0x80000000 images/spi-nand.bin

Then, on the running U-Boot console:

=> mtd erase boot
=> mtd write.raw boot 0x80000000
=> reset

The raw write.raw is important — mtd write would re-apply ECC/OOB on top of what is already there, mangling the image.

Gotchas

LEB size: the UBIFS image produced by Buildroot must match the LEB size of the runtime UBI device, otherwise mounting fails. See SPI NAND Partitioning.
reset not supported: some U-Boot defconfigs miss the watchdog reset driver and print System reset not supported on this platform. Power-cycle in that case, then fix the defconfig.
Wrong Image Type for bootm command: use the FIT image (see image.its in the board files).