I ran a rolling update on my Pinebook Pro yesterday, and after rebooting, SDDM failed to start and the screen stayed black.
After some troubleshooting, I found the cause. I posted the details in the issue here:
https://github.com/endeavouros-arm/PKGBUILDS/issues/7
The fix is to install libdrm and replace libdrm-pinebookpro.
If anyone else is having the same issue, you can give this a try.
You’re luckier than me : I’ve an issue with GUI too for several days, but half an hour ago, I’ve pacman -Syu and now my WIFI won’t connect the Internet 
Actually, lol, my pinebookpro WiFi is acting up too — it keeps reconnecting intermittently after connecting, so I’m using an external USB WiFi adapter right now.
Managed to get working wifi 
Also, replaced libdrm-pinebookpro with libdrm : no more crashes (more than 20 from /usr/bin/kaccess before that)!
But a problem remains : the resolution of the desktop is stuck at 1024x768 whereas my screen display is 1920x1080.
It’s a bit strange. It looks normal on my end, with the screen displayed at 1920×1080 resolution.
Have you tried going into Plasma settings to adjust the screen resolution-related options?
I did but this tool is broken: no mouse, no trackpad can be detected and 1024x768 is the only option. I’ve managed to get a functional trackpad by setting some options in an xorg.conf file and starting with startx /usr/lib/startplasma-wayland but that is not enough to configure display.
First off, @yjun Welcome to the EndeavourOS forum. I hope you enjoy your time here.
Sorry, I didn’t see this Topic until after I posted this:
Pudge
Did you start Plasma using X11 or Wayland?
Hi Pudge, does the built-in WiFi on your Pinebook Pro work properly? I’ve found mine to be really unstable — it keeps reconnecting after a while, which is pretty annoying. Right now I’m using an external USB WiFi adapter instead.
Wayland
My WiFi works well for me. The Pinebook Pro is only 18 to 20 feet from the router, on the same floor, and one wall between. I test the WiFi every time I test a new image and it seems stable. But I don’t use it for any prolonged amount of time.
I have a Raspberry Pi 4b that I use as a Simple Home LAN server. All my Music, Photos, Videos, and important files on the LAN server. For security purposes, I set up the LAN server for ethernet access only. So I have a Ethernet to USB converter that I run on most of the time.
Pudge