reboot command hangs with no screen signal on ODROID HC4

[meruby]

Hi, all. I'm using ODROID HC4-P KIT.

Installing Arch Linux ARM for ODROID HC4, referring [url]https://archdroid.org/en/images/odroidc4/[/url] , is fine. I tried to both GNOME and Xfce images.
But when executing 'reboot' command after installation, via Terminal program, the system is shutdown and fan is working but there are no screen signal at all.

It will be thankful if someone helps me.
Thanks.