Drop special handling of grub modules, adding a note. Modules should be included in the signed grub binaries when necessary.

live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary

@@ -62,30 +62,21 @@ install_grub() {
     efi_boot_dir="/boot/efi/EFI/BOOT"
     chroot mountpoint mkdir -p "${efi_boot_dir}"
 
-    # The modules below only make sense on non-Secure Boot UEFI systems.
-    # Otherwise, with Secure Boot enabled GRUB will refuse to load them.
-    # Any modules already in debian/build-efi-images do not need to be listed.
-    # Furthermore, other modules such as terminal, video_* and efi_* are all
-    # already available.
+    # UEFI GRUB modules are meant to be used equally by Secure Boot and
+    # non-Secure Boot systems. If you need an extra module not already
+    # provided or run into "Secure Boot policy forbids loading X" problems,
+    # please file a bug against grub2 to include the affected module.
     case $ARCH in
         arm64)
             chroot mountpoint apt-get -qqy install --no-install-recommends grub-efi-arm64 grub-efi-arm64-bin
-            grub_modules="serial"
             efi_target=arm64-efi
             ;;
         amd64)
             chroot mountpoint apt-get install -qqy grub-efi-amd64-signed grub-efi-amd64 shim-signed
-            grub_modules="multiboot serial usb usb_keyboard"
             efi_target=x86_64-efi
             ;;
     esac
 
-    cat << EOF >> mountpoint/etc/default/grub.d/50-cloudimg-settings.cfg
-${IMAGE_STR}
-# For Cloud Image compatability
-GRUB_PRELOAD_MODULES="${GRUB_PRELOAD_MODULES:-$grub_modules}"
-EOF
-
     chroot mountpoint grub-install "${loop_device}" \
         --boot-directory=/boot \
         --efi-directory=/boot/efi \