You'll want to follow the instructions laid out on this wiki page to clear the SPI: https://wiki.pine64.org/wiki/Pinebook_Pr...e%2C%20you or this forum post: https://forum.pine64.org/showthread.php?tid=11976
I'd suggest to make an SD for installing tow boot with this img: https://github.com/Tow-Boot/Tow-Boot/rel...007.tar.xz
following the instructions provided here to install it: https://tow-boot.org/devices/pine64-pinebookPro.html
I'd suggest to make an SD for installing tow boot with this img: https://github.com/Tow-Boot/Tow-Boot/rel...007.tar.xz
following the instructions provided here to install it: https://tow-boot.org/devices/pine64-pinebookPro.html