hide grub menu and initial loading message

With Debian 9.9 and GNOME 3.22, I'm trying to load the OS without boot menu. I've installed plymouth to show a graphical loading and set this options in grub: GRUB_DEFAULT=0 GRUB_TIMEOUT=0 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true But for a split second, I still see some kind of grub menu. This time with no options. What I see is an image located here /usr/share/images/desktop-base/desktop-grub.png, and a text that says loading linux 4.9.0-9-amd64... loading initial memory image... Then plymouth theme is shown and normal boot happens. Is it possible to hide this? I would like to just see the theme