grub 2.02beta3-5 console with german keymap - freezes / no input

[IGP AG, IT Support]

Hello,

I tried editing the debian 9.5 ISO to give the grub console a german keyboard, 
steps below. As soon as I load "terminal_input at_keyboard" I can't perform any 
more input / it appears frozen.

I also found these bugs which could match this case, but I can't imagine this 
is not fixed yet...

grub-pc-bin: freezes after "terminal_input at_keyboard"
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=741464

No input on usb keyboard after terminal_input at_keyboard command
http://savannah.gnu.org/bugs/?func=detailitem&item_id=50232


  1.  Use debian to create german keyboard file
     *   grub-kbdcomp -o /root/grub-kbd-de.gkb de
  2.  Edit debian 9.5 ISO
     *   Add grub-kbd-de.gkb to /boot/grub/layouts
     *   Modify grub.cfg to allow keymap and use at_keyboard

                                                               i.      insmod 
keylayouts

                                                             ii.      keymap 
grub-kbd-de

                                                           iii.      insmod 
at_keyboard

                                                           iv.      
terminal_input at_keyboard

  1.  boot from edited ISO in hyperv (win10-RS4)
     *   => freeze /no input possible

I also performed the grub commands in 2.b manually, also tried different order, 
no change.

Kind regards,
Volker Badziong