now head over here: https://github.com/BPI-SINOVOIP/bpi-tools
All needed from there is:
curl -sL https://github.com/BPI-SINOVOIP/bpi-tools/raw/master/bpi-tools | sudo -E bash -
on your board.
When tools are installed you can just use them for pretty straight forward updates.
1st one (when booted via sw4 on 0) to point to SD card for operations (mmcblk0 is internal at this point):
bpi-update -c bpi-w2.conf -d mmcblk1
this will get config file and all files mentioned there, unpack files for p1, set kernel modules on p2 …
then you can just run this:
it will list uboot images available on your board and how to use it.
For some reason -c [conffile] was not working for me but it was fine when triggered manually (make sure this path is there after initial run of the command:
bpi-bootsel /usr/lib/u-boot/bananapi/BPI-W2-720P-2k.img.gz /dev/mmcblk1
Power off the board, switch sw4 to 1 and boot up again. It will boot from SD with kernel 4.9.
From quick glance at tools code it looks like you will need to remove bpi-w2.conf for next release (it checks if the file is there before trying to download fresh one from github)
When booted with sw4 on 1 your SD card is mmcblk0 so that part can be left out when invoking same stuff again (mmcblk0 is default target)