diff --git a/debian/changelog b/debian/changelog
index 149ebb967..d78f56378 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+grub2 (2.02~beta2-28) UNRELEASED; urgency=medium
+
+  * Reduce the CFLAGS -O3 default on Ubuntu ppc64el to -O2; it introduces
+    various -Werror failures and isn't worth it here.
+
+ -- Colin Watson <cjwatson@debian.org>  Sat, 05 Sep 2015 19:08:28 +0100
+
 grub2 (2.02~beta2-27) unstable; urgency=medium
 
   [ Felix Zielcke ]
diff --git a/debian/rules b/debian/rules
index 97b96ae6c..cc192ce93 100755
--- a/debian/rules
+++ b/debian/rules
@@ -11,7 +11,9 @@ DEB_HOST_ARCH_OS ?= $(shell dpkg-architecture -qDEB_HOST_ARCH_OS 2>/dev/null)
 DEB_HOST_ARCH_CPU ?= $(shell dpkg-architecture -qDEB_HOST_ARCH_CPU 2>/dev/null)
 
 HOST_CPPFLAGS := $(shell dpkg-buildflags --get CPPFLAGS)
-HOST_CFLAGS := -Wall -Wno-error=unused-result $(shell dpkg-buildflags --get CFLAGS)
+# -O3 (default on Ubuntu ppc64el) introduces various -Werror failures, and
+# isn't worth it here.
+HOST_CFLAGS := -Wall -Wno-error=unused-result $(shell dpkg-buildflags --get CFLAGS | perl -pe 's/-O3\b/-O2/')
 HOST_LDFLAGS := $(shell dpkg-buildflags --get LDFLAGS)
 
 unexport CFLAGS