From: Andrey Borzenkov <arvidjaar@gmail.com>
Date: Fri Jan  4 09:46:56 UTC 2013
Subject: skip legacy Microsoft bootloader on UEFI system

References: bnc#775610
Patch-Mainline: no

Sometimes Windows installs both legacy BIOS and UEFI bootloaders.
Attempt to chainload legacy bootloader on UEFI system fails. Skip
adding legacy bootloader in this case.

TODO: this probably should be implemented as runtime check. But it
does the right thing in majority of cases. If mixed legacy/UEFI
boot will be used frequently, it can be revisited.
Index: os-prober/os-probes/mounted/x86/20microsoft
===================================================================
--- os-prober.orig/os-probes/mounted/x86/20microsoft
+++ os-prober/os-probes/mounted/x86/20microsoft
@@ -7,6 +7,12 @@ partition="$1"
 mpoint="$2"
 type="$3"
 
+# This script looks for legacy BIOS bootloaders only. Skip if running UEFI
+if [ -d /sys/firmware/efi ]; then
+	debug "Skipping legacy bootloaders on UEFI system"
+	exit 1
+fi
+
 # Weed out stuff that doesn't apply to us
 case "$type" in
 	ntfs|ntfs-3g) debug "$1 is a NTFS partition" ;;