Prepare Pinebook Pro for Sale

[GFreeman]

Depends on how thorough/paranoid you want to do it.
You can flash it again and fill up the remaining space with random files.

You can use videos from Blender (copyright free) and keep copying them until your drive is (close to) full.
But it is better to leave several MB free, as you might run into problems with log files.
https://4kmedia.org/big-buck-bunny-4k-demo/

Or you can boot from a micro SD card and format the eMMC (not a quick format) and flash the eMMC again.
And when you feel like it, you can fill up the remaining space with random files.

In ultimate paranoid mode, you sell it without the eMMC.

Hello,

This is great. Thank you very much.

As a follow-up question, how would I go about ultimate paranoid mode and sell it without the eMMC?

Best,

Graham