BPI-W2 android 7.1.1 Demo Version
Download image, unzip the file.
Copy the file “install.img”, to your usb disk.
Plug your usb disk in W2.
Use usb-serial to connect W2, open a console terminal on your PC.
Then power on W2, and press “Tab” button on PC to update image in your W2.
Image link :
Baidu drive: https://pan.baidu.com/s/1WP_TRe9PeNZvfi5bEJy0AQ