fix(grub): Fix failure to boot when using standalone mode.

When introducing grub.d integration, we switched to using the already-
installed grub binary if it existed. But this is not a good idea,
because it may come with hardcoded paths which may fail to load the
script that we put in `/EFI/BOOT`. So revert to the old behavior,
install our own pre-compiled grub binary if grub.d integration is off.

No changelog, since we never released this regression.

Changelog: None
Ticket: None

Signed-off-by: Kristian Amlie <kristian.amlie@northern.tech>

mender-convert-modify

@@ -140,21 +140,21 @@ if [ "${MENDER_GRUB_EFI_INTEGRATION}" == "y" ]; then
     # Check for known U-Boot problems in all files on the boot partition.
     check_for_broken_uboot_uefi_support work/boot
 
-    if has_grub_efi "work/boot"; then
+    if [ "$MENDER_GRUB_D_INTEGRATION" = y ] || ( [ "$MENDER_GRUB_D_INTEGRATION" = auto ] && supports_grub_d "work/rootfs" ); then
         # No need to install Grub, use the one already present, and only install
         # our tools.
-        log_info "GRUB EFI bootloader already present, not installing one."
+        log_info "Not installing GRUB EFI bootloader, relying on platform provided one."
+
+        log_info "Installing Mender GRUB tools..."
         grub_install_grub_editenv_binary
-    else
-        log_info "Installing GRUB EFI bootloader..."
-        grub_install_mender_grub
-    fi
 
-    if [ "$MENDER_GRUB_D_INTEGRATION" = y ] || ( [ "$MENDER_GRUB_D_INTEGRATION" = auto ] && supports_grub_d "work/rootfs" ); then
         log_info "Generating grub config using update-grub..."
         grub_create_grub_config
         grub_install_grub_d_config
     else
+        log_info "Installing GRUB EFI bootloader..."
+        grub_install_mender_grub
+
         log_info "Generating the mender-grub config..."
         grub_create_grub_config
         grub_install_standalone_grub_config

modules/probe.sh

@@ -345,15 +345,6 @@ is_efi_compatible_kernel() {
     return 0
 }
 
-# has_grub_efi
-#
-# $1 - the boot partition to search for a grub*.efi
-#
-# Checks the EFI/* filesystem for the presence of a GRUB bootloader
-has_grub_efi() {
-    find "${1}" -type f -name 'grub*.efi' -print0 | grep -qz grub
-}
-
 supports_grub_d() {
     test -d "$1"/etc/grub.d || return 1