diff --git a/_constraints b/_constraints
index 7a401ec..a42ffec 100644
--- a/_constraints
+++ b/_constraints
@@ -6,7 +6,7 @@
       <size unit="G">4</size>
     </memory>
     <disk>
-      <size unit="G">40</size>
+      <size unit="G">20</size>
     </disk>
   </hardware>
   <overwrite>
diff --git a/rust.changes b/rust.changes
index 0249db5..a937051 100644
--- a/rust.changes
+++ b/rust.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Wed Feb 15 05:58:35 UTC 2017 - luke.nukem.jones@gmail.com
+
+- Fixes to build for archs armv7, aarch64, ppc64, s390x
+
 -------------------------------------------------------------------
 Sat Feb 11 05:31:34 UTC 2017 - luke.nukem.jones@gmail.com
 
diff --git a/rust.spec b/rust.spec
index c03d057..c3d90e9 100644
--- a/rust.spec
+++ b/rust.spec
@@ -62,17 +62,21 @@ Conflicts:      rustc-bootstrap
 Provides:       rustc = %{version}
 Provides:       rustc-stable = %{version}
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
+# Restrict the architectures as building rust relies on being initially
+# bootstrapped before we can build the n+1 release
 ExclusiveArch:  %{ix86} x86_64 %{arm} aarch64 ppc64 ppc64le s390x
 
 %if 0%{?suse_version}
 BuildRequires:  fdupes
 %endif
 
-%ifarch %{arm} aarch64 ppc64 ppc64le s390x
+%ifarch s390x
 BuildRequires:  cargo-bootstrap
 BuildRequires:  rustc-bootstrap >= %{prev_version}
 %else
-%if %{with bootstrap} || (0%{?suse_version} < 1330 && 0%{?sle_version} < 120300)
+# There are no successful builds for less than TW or Leap 42.2, so bootstrap
+# until such time that there is.
+%if %{with bootstrap} || (0%{?suse_version} < 1330 && 0%{?sle_version} <= 120100)
 BuildRequires:  cargo-bootstrap
 BuildRequires:  rustc-bootstrap >= %{prev_version}
 %else