diff --git a/os-porber-no-dummy-mach-kernel.patch b/os-porber-no-dummy-mach-kernel.patch
new file mode 100644
index 0000000..7c16af9
--- /dev/null
+++ b/os-porber-no-dummy-mach-kernel.patch
@@ -0,0 +1,25 @@
+From f71f7eb5c492720c24033901ef8c6c420e188ff2 Mon Sep 17 00:00:00 2001
+From: Peter Jones <pjones@redhat.com>
+Date: Thu, 10 May 2012 14:47:35 -0400
+Subject: [PATCH] Don't count our dummy mach_kernel as real MacOS X.
+
+---
+ os-probes/mounted/powerpc/20macosx |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/os-probes/mounted/powerpc/20macosx b/os-probes/mounted/powerpc/20macosx
+index dd4207f..d630fec 100755
+--- a/os-probes/mounted/powerpc/20macosx
++++ b/os-probes/mounted/powerpc/20macosx
+@@ -21,7 +21,7 @@ esac
+ # but I don't think it exists on Mac OS <= 9, and it's XML so parsing in
+ # shell will be nasty.
+ 
+-if [ -e "$2/mach_kernel" ]; then
++if [ -e "$2/mach_kernel" ] && ! dd if="$2/mach_kernel" count=1 bs=5 2>/dev/null | grep -q Dummy ; then
+   label="$(count_next_label MacOSX)"
+   result "$1:Mac OS X:$label:macosx"
+   exit 0
+-- 
+1.7.10.1
+
diff --git a/os-prober.spec b/os-prober.spec
index 44006c8..ce973db 100644
--- a/os-prober.spec
+++ b/os-prober.spec
@@ -1,6 +1,6 @@
 Name:           os-prober
 Version:        1.52
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        Probes disks on the system for installed operating systems
 
 Group:          System Environment/Base
@@ -11,9 +11,10 @@ Source0:        http://ftp.de.debian.org/debian/pool/main/o/os-prober/%{name}_%{
 # move newns binary outside of os-prober subdirectory, so that debuginfo
 # can be automatically generated for it
 Patch0:         os-prober-newnsdirfix.patch
+Patch1:		os-porber-no-dummy-mach-kernel.patch
 
 Requires:       udev coreutils util-linux
-Requires:       /bin/grep /bin/sed /sbin/modprobe
+Requires:       grep /bin/sed /sbin/modprobe
 
 %description
 This package detects other OSes available on a system and outputs the results
@@ -23,6 +24,7 @@ distributions can be added easily.
 %prep
 %setup -q -n %{name}
 %patch0 -p1 -b .newnsdirfix
+%patch1 -p1 -b .macosxdummyfix
 find -type f -exec sed -i -e 's|usr/lib|usr/libexec|g' {} \;
 sed -i -e 's|grub-probe|grub2-probe|g' os-probes/common/50mounted-tests \
      linux-boot-probes/common/50mounted-tests
@@ -72,6 +74,10 @@ fi
 %{_var}/lib/%{name}
 
 %changelog
+* Thu May 10 2012 Peter Jones <pjones@redhat.com> - 1.52-3
+- Don't detect our Mac boot blocks as OS X.
+  Resolves: rhbz#811412
+
 * Sun Apr 29 2012 Hedayat Vatankhah <hedayat.fwd+rpmchlog@gmail.com> - 1.52-2
 - use correct directory name for setup