grub-install: Allow to install to non-EFI ESP when --force

Although the EFI specification enforces support for FAT ESP, it's free
for EFI implementations to implement support for ESPs with other formats
(e.g. ext4, ntfs, etc), and at least U-Boot EFI will support ext4 ESP if
U-Boot is built with ext4 support. In some situations a GRUB installation
on such a non-FAT ESP could be useful (e.g. a NTFS-based USB disk that
can dual boot a Windows installation media and a Linux LiveCD).

As this is advanced and implementation-dependent behavior, let grub-install
allow this kind of installation, but only when --force is specified.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/util/grub-install.c b/util/grub-install.c
index d601c3e8df275be99ecf9d2ef61846114140783c..7b04bd3c534b6f70302adf9340e2216a8c31eb2c 100644 (file)
--- a/util/grub-install.c
+++ b/util/grub-install.c
@@ -1092,7 +1092,12 @@ main (int argc, char *argv[])
        efidir_is_mac = 1;
 
       if (!efidir_is_mac && grub_strcmp (fs->name, "fat") != 0)
-       grub_util_error (_("%s doesn't look like an EFI partition"), efidir);
+       {
+         if (force)
+           grub_util_warn (_("%s doesn't look like an EFI partition, system may not boot"), efidir);
+         else
+           grub_util_error (_("%s doesn't look like an EFI partition"), efidir);
+       }
 
       /* The EFI specification requires that an EFI System Partition must
         contain an "EFI" subdirectory, and that OS loaders are stored in