From 7cf3ac7be59ef377a98ead5c7d3d5cb537c159c4 Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@ubuntu.com>
Date: Mon, 13 Jan 2014 12:13:05 +0000
Subject: Fall back to non-EFI if booted using EFI but -efi is missing

It may be possible, particularly in recovery situations, to be booted
using EFI on x86 when only the i386-pc target is installed, or on ARM
when only the arm-uboot target is installed.  There's nothing actually
stopping us installing i386-pc or arm-uboot from an EFI environment, and
it's better than returning a confusing error.

Author: Steve McIntyre <93sam@debian.org>
Forwarded: no
Last-Update: 2019-05-24

Patch-Name: install-efi-fallback.patch
---
 grub-core/osdep/linux/platform.c | 40 ++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/grub-core/osdep/linux/platform.c b/grub-core/osdep/linux/platform.c
index e28a79dab..2e7f72086 100644
--- a/grub-core/osdep/linux/platform.c
+++ b/grub-core/osdep/linux/platform.c
@@ -19,10 +19,12 @@
 #include <config.h>
 
 #include <grub/util/install.h>
+#include <grub/emu/config.h>
 #include <grub/emu/exec.h>
 #include <grub/emu/misc.h>
 #include <sys/types.h>
 #include <dirent.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include <sys/utsname.h>
@@ -128,9 +130,24 @@ const char *
 grub_install_get_default_arm_platform (void)
 {
   if (is_efi_system())
-    return "arm-efi";
-  else
-    return "arm-uboot";
+    {
+      const char *pkglibdir = grub_util_get_pkglibdir ();
+      const char *platform;
+      char *pd;
+      int found;
+
+      platform = "arm-efi";
+
+      pd = grub_util_path_concat (2, pkglibdir, platform);
+      found = grub_util_is_directory (pd);
+      free (pd);
+      if (found)
+	return platform;
+      else
+	grub_util_info ("... but %s platform not available", platform);
+    }
+
+  return "arm-uboot";
 }
 
 const char *
@@ -138,10 +155,23 @@ grub_install_get_default_x86_platform (void)
 {
   if (is_efi_system())
     {
+      const char *pkglibdir = grub_util_get_pkglibdir ();
+      const char *platform;
+      char *pd;
+      int found;
+
       if (read_platform_size() == 64)
-	return "x86_64-efi";
+	platform = "x86_64-efi";
+      else
+	platform = "i386-efi";
+
+      pd = grub_util_path_concat (2, pkglibdir, platform);
+      found = grub_util_is_directory (pd);
+      free (pd);
+      if (found)
+	return platform;
       else
-	return "i386-efi";
+	grub_util_info ("... but %s platform not available", platform);
     }
 
   grub_util_info ("Looking for /proc/device-tree ..");