Dietpi v8.18.2 + Odroid C4: Same old problems: a) Video bug, b) missing Overlays, c) Boot speed

Hello, I am just testing
DietPi v8.18.2 : Released 5.6.2023

Linux DietPi 6.1.11-meson64 #23.02.2 SMP PREEMPT Sat Feb 18 00:07:55 UTC 2023 aarch64 GNU/Linux

root@DietPi:/boot# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 11 (bullseye)
Release: 11
Codename: bullseye

—> It is not the newest Kernel 6.3.x, but I doubt it contains all overlays for Odroid C4 anyway.

Needed diskspace after X-Window-Install :
/dev/mmcblk1p1 7,2G 1,6G 5,4G 22% /

Overlays for Odroid C4:
→ Missing overlays : uartB, PCF8563 (Realtimeclock) ; I absolutely require both i.e. 3

Connected to my Odroid C4 is a Waveshare 7" touch screen with a standard resolution of 1024x600.
Even in textmode, 20 rasterlines are hanging down, whose color depend on the mouse position near the left/down corner. This bug is NOT present in Kernel 4.9, but IS present in all Kernels 5, 6, and all distros who use Kernel 5 or 6.

Audio devices are properly displayed (HDMI).

Wiring PI installation worked out of the box.

Booting time: 25 seconds after switch-on; maybe 5 seconds wasted with network.

6.714s ifup@eth0.service
1.086s ifupdown-pre.service
 982ms dev-mmcblk1p1.device
 385ms systemd-udev-trigger.service
 371ms user@1000.service
 336ms upower.service
 293ms dietpi-preboot.service
 286ms user@0.service
 240ms keyboard-setup.service
 182ms systemd-logind.service
 179ms systemd-journald.service
 166ms systemd-timesyncd.service
 134ms cups.service
 120ms ssh.service
 115ms networking.service
 114ms dev-hugepages.mount
 113ms modprobe@fuse.service
 111ms dev-mqueue.mount
 110ms sys-kernel-debug.mount
 109ms modprobe@drm.service
 104ms modprobe@configfs.service
 104ms fake-hwclock.service
 103ms dietpi-ramlog.service
  96ms kmod-static-nodes.service
  90ms systemd-modules-load.service
  89ms lightdm.service
  89ms systemd-remount-fs.service
  87ms avahi-daemon.service
  77ms systemd-udevd.service
  63ms sys-fs-fuse-connections.mount
  60ms sys-kernel-config.mount
  48ms systemd-tmpfiles-setup.service
  40ms systemd-random-seed.service
  37ms systemd-sysctl.service
  33ms systemd-sysusers.service
  32ms systemd-tmpfiles-setup-dev.service
  31ms user-runtime-dir@0.service
  31ms user-runtime-dir@1000.service
  30ms systemd-update-utmp.service
  29ms polkit.service
  26ms systemd-journal-flush.service
  26ms systemd-update-utmp-runlevel.service
  25ms systemd-user-sessions.service
  19ms console-setup.service
  15ms tmp.mount
  13ms alsa-restore.service
  12ms var-log.mount
   8ms vsftpd.service

The booting time told by the system is not matching the hand-stopped 25 seconds:

root@DietPi:~# systemd-analyze
Startup finished in 4.141s (kernel) + 10.292s (userspace) = 14.434s reached after 10.232s in userspace

I really need this stupid graphics bug to disappear, and I need more overlays so more hardware is going to work (UART A+B+C , Realtime clock PCF8563).

Is nobody able in years to remove this simple graphics bug of hanging down raster lines at the 1024x600 resolution?
No, chaning Firmware and editing EDID files etc. did not help either, because it did not help previously.

to avoid a missunderstanding. We don’t do any kernel development, nor create overleay. Overlays would need to be activated manually if needed. Maybe something @MichaIng could help with.

Note that those overlays you are missing are vendor kernel only overlays. They never existed in upstream/mainline linux and you can blame the vendor/manufacturer for never adding them or providing them for mainline linux, but only for their own ancient, nowadays unusable Linux forks (the Linux 4.9 you mentioned).

The overlays you see are also not part of mainline Linux code bit written by Armbian guys for their Linux builds. Note that they do not necessarily work on Odroid C4 but most (if I remember right) work on Odroid C2 only. Armbian never added some differentiation for this.

There are some topics about specific GPIO features here, which might give hints about how to enable those features (writing own overlays). I’ll see if I find them.