A:
I was finally able to workaround the problem here.
The script /etc/grub.d/00_header does some font path detection stuff and if that fails it doesn't set any gfxmode (neither the default "auto" nor anything defined manually in /etc/default/grub).
The font path is /usr/share/grub, but I have a separate /boot partition and the script doesn't seem to know how to handle this situation correctly, leaving me without fonts and gfxmode.
So, I just copied /usr/share/grub/*.pf2 to /boot/grub and ran update-grub again. Voila, I got my gfxmode and a working unicode font, too.
但是还是不好使，下面方法成功了。
Running these commands fixed it for me:
sudo chmod a-x /etc/grub.d/05_debian_theme sudo update-grub sudo reboot 文章来源: https://blog.csdn.net/qq_38428855/article/details/88851814