If you messed up the system on the internal eMMC flash, you can use an SD card to boot the computer.
(if you already know how to flash an image for a raspberry pi, it's the same process).
Download the Image from the Manjaro website: (choose the ARM edition for Pinebook Pro, with the desktop environment of your choice. KDE is the default)
https://osdn.net/projects/manjaro-arm/st....04.img.xz
Unpack the .xz file on your computer (use 7-zip on Windows, xz -d on Linux/Mac).
Flash the resulting .img file to an SD card (
https://www.balena.io/etcher/ or dd on Linux/Mac)
You can plug this into the Pinebook and it will boot from the SD card.
If your system is broken, you might need to hard-reset the machine by holding the power button for ~10 seconds to turn it off completely.
Then you can turn it back on normally.
You're now running Manjaro, but from the SD card slot. That works, but it's slower, but you can now flash a new image to the internal eMMC flash.
In a terminal you can do:
Code:
wget "https://osdn.net/projects/manjaro-arm/storage/pbpro/kde-plasma/20.04/Manjaro-ARM-kde-plasma-pbpro-20.04.img.xz"
xz -d Manjaro-ARM-kde-plasma-pbpro-20.04.img.xz
sudo dd if=Manjaro-ARM-kde-plasma-pbpro-20.04.img of=/dev/mmcblk2 bs=8M status=progress
Enter your password and wait for it to finish. Shutdown the Manjaro installation properly and remove the SD card.
You can now start the computer normally from eMMC.
Good luck,
Tobias