Now I have new errors. It seems that OpenPnP can't find some graphics indeed. Something like awt.Toolkit and others are missing.
Also tried installing different Java versions like 1.8 for 32bit(does not work at all), and embedded Java for ARMv7. Still no success.
Please help if anyone knows where the problem is. Thanks :)
java.lang.UnsatisfiedLinkError: Can't load library: /usr/lib/jvm/jdk1.8.0_241/jre/lib/aarch64/libawt_xawt.so
  at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1820)
  at java.lang.Runtime.load0(Runtime.java:809)
  at java.lang.System.load(System.java:1086)
  at java.lang.ClassLoader$NativeLibrary.load(Native Method)
  at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1934)
  at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1838)
  at java.lang.Runtime.loadLibrary0(Runtime.java:870)
  at java.lang.System.loadLibrary(System.java:1122)
  at java.awt.Toolkit$3.run(Toolkit.java:1636)
  at java.awt.Toolkit$3.run(Toolkit.java:1634)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.awt.Toolkit.loadLibraries(Toolkit.java:1633)
  at java.awt.Toolkit.<clinit>(Toolkit.java:1670)
  at javax.swing.UIManager.getSystemLookAndFeelClassName(UIManager.java:611)
  at org.openpnp.Main.main(Main.java:129)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:62)
  at com.install4j.runtime.launcher.UnixLauncher.main(UnixLauncher.java:57)
java.lang.NoClassDefFoundError: Could not initialize class java.awt.Toolkit
  at java.awt.EventQueue.invokeLater(EventQueue.java:1294)
  at com.exe4j.runtime.LauncherEngine.handleFailure(LauncherEngine.java:109)
  at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:65)
  at com.install4j.runtime.launcher.UnixLauncher.main(UnixLauncher.java:57)
Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class java.awt.Toolkit
  at java.awt.EventQueue.invokeLater(EventQueue.java:1294)
  at com.exe4j.runtime.LauncherEngine.handleFailure(LauncherEngine.java:109)
  at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:71)
  at com.install4j.runtime.launcher.UnixLauncher.main(UnixLauncher.java:57)