diff --git a/20000-efi-chainloader-fix-wrong-sanity-check-in-relocate_c.patch b/20000-efi-chainloader-fix-wrong-sanity-check-in-relocate_c.patch
new file mode 100644
index 0000000..93bbe53
--- /dev/null
+++ b/20000-efi-chainloader-fix-wrong-sanity-check-in-relocate_c.patch
@@ -0,0 +1,38 @@
+From 725f07ed1e4e18836f54a0a798a8b1e720fae783 Mon Sep 17 00:00:00 2001
+From: Laszlo Ersek <lersek@redhat.com>
+Date: Mon, 21 Nov 2016 15:34:00 +0100
+Subject: [PATCH] efi/chainloader: fix wrong sanity check in relocate_coff()
+
+In relocate_coff(), the relocation entries are parsed from the original
+image (not the section-wise copied image). The original image is
+pointed-to by the "orig" pointer. The current check
+
+  (void *)reloc_end < data
+
+compares the addresses of independent memory allocations. "data" is a typo
+here, it should be "orig".
+
+Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1347291
+Signed-off-by: Laszlo Ersek <lersek@redhat.com>
+Tested-by: Bogdan Costescu <bcostescu@gmail.com>
+Tested-by: Juan Orti <j.orti.alcaine@gmail.com>
+---
+ grub-core/loader/efi/chainloader.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
+index 49a7662fa605..1bd7ffb3160e 100644
+--- a/grub-core/loader/efi/chainloader.c
++++ b/grub-core/loader/efi/chainloader.c
+@@ -397,7 +397,7 @@ relocate_coff (pe_coff_loader_image_context_t *context,
+       reloc_end = (struct grub_pe32_fixup_block *)
+ 	((char *)reloc_base + reloc_base->size);
+ 
+-      if ((void *)reloc_end < data || (void *)reloc_end > image_end)
++      if ((void *)reloc_end < orig || (void *)reloc_end > image_end)
+         {
+           grub_error (GRUB_ERR_BAD_ARGUMENT, "Reloc entry %d overflows binary",
+ 		      n);
+-- 
+2.9.2
+
diff --git a/grub2.spec b/grub2.spec
index 4458ffd..47973db 100644
--- a/grub2.spec
+++ b/grub2.spec
@@ -45,7 +45,7 @@
 Name:           grub2
 Epoch:          1
 Version:        2.02
-Release:        0.34%{?dist}
+Release:        0.35%{?dist}
 Summary:        Bootloader with support for Linux, Multiboot and more
 
 Group:          System Environment/Base
@@ -72,6 +72,12 @@ Patch10004: 10004-Add-grub_qdprintf-grub_dprintf-without-the-file-lin.patch
 Patch10005: 10005-Make-a-gdb-dprintf-that-tells-us-load-addresses.patch
 #Patch10006: 10006-Try-it-in-gentpl-again.patch
 
+# This is: https://bugzilla.redhat.com/attachment.cgi?id=1222471
+# From: https://bugzilla.redhat.com/show_bug.cgi?id=1347291
+# Patch by Laszlo Ersek to fix a bad sanity check which causes issues
+# with UEFI Windows dual boot. Should be sent upstream.
+Patch20000: 20000-efi-chainloader-fix-wrong-sanity-check-in-relocate_c.patch
+
 BuildRequires:  flex bison binutils python
 BuildRequires:  ncurses-devel xz-devel bzip2-devel
 BuildRequires:  freetype-devel libusb-devel
@@ -547,6 +553,8 @@ fi
 %changelog
 * Thu Dec 01 2016 Peter Jones <pjones@redhat.com> - 2.02-0.34
 - Fix power6 makefile bits for newer autoconf defaults.
+- efi/chainloader: fix wrong sanity check in relocate_coff() (Laszlo Ersek)
+  Resolves: rhbz#1347291
 
 * Thu Aug 25 2016 Peter Jones <pjones@redhat.com> - 2.02-0.34
 - Update to be newer than f24's branch.