diff --git a/installation-images.changes b/installation-images.changes
index 1c63ce1..45f9fdd 100644
--- a/installation-images.changes
+++ b/installation-images.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Mon May 29 10:16:28 CEST 2017 - snwint@suse.de
+
+- rewrite spec file to simplify building different flavors (bsc#1039285)
+
 -------------------------------------------------------------------
 Tue May 16 10:28:55 CEST 2017 - snwint@suse.de
 
diff --git a/installation-images.spec b/installation-images.spec
index b86ea8b..ba71454 100644
--- a/installation-images.spec
+++ b/installation-images.spec
@@ -22,7 +22,6 @@
 ExclusiveArch:  do_not_build
 %endif
 
-# xxx
 %global flavor @BUILD_FLAVOR@%nil
 
 %define with_vbox 0
@@ -33,30 +32,47 @@ ExclusiveArch:  do_not_build
 %bcond_with xen
 %bcond_with xenkmp
 
-# ===  sort out branding  ===
+# ===  sort out which flavor to build  ===
+
+%if "%flavor" == "openSUSE"
 %if 0%{?is_opensuse}
-%if "%flavor" == "Kubic"
-%if 0%{?sle_version}
-# don't build on Leap for now
-ExclusiveArch:  do_not_build
-%endif
-%define theme Kubic
-%define product_nameX %{theme}-%{_target_cpu}
-%define branding_skelcd   CAASP
-%define branding_systemd  CAASP
-%define branding_plymouth openSUSE
-%define branding_grub2    openSUSE
-%define branding_gfxboot  openSUSE
-BuildRequires:  openSUSE-Kubic-release
-%ifnarch s390x
-BuildRequires:  xf86-input-libinput
-%endif
-%else
-%if "%flavor" != "openSUSE"
-ExclusiveArch:  do_not_build
-%endif
 %define theme openSUSE
-%define product_nameX %{theme}-%{_target_cpu}
+%endif
+%endif
+
+%if "%flavor" == "Kubic"
+# don't build on Leap for now
+%if 0%{?is_opensuse} && !0%{?sle_version}
+%define theme Kubic
+%endif
+%endif
+
+%if "%flavor" == "SLED"
+# build SLED only on x86_64
+%if "%{_target_cpu}" == "x86_64" && 0%{?sle_version} && !0%{?is_opensuse}
+%define theme SLED
+%endif
+%endif
+
+%if "%flavor" == "SLES"
+%if 0%{?sle_version} && !0%{?is_opensuse}
+%define theme SLES
+%endif
+%endif
+
+%if "%flavor" == "CAASP"
+%if 0%{?is_susecaasp}
+%define theme CAASP
+%endif
+%endif
+
+# ===  define each theme  ===
+
+%if "%{?theme}" == ""
+ExclusiveArch:  do_not_build
+%endif
+
+%if "%theme" == "openSUSE"
 %define branding_skelcd   openSUSE
 %define branding_systemd  openSUSE
 %define branding_plymouth openSUSE
@@ -67,28 +83,33 @@ BuildRequires:  openSUSE-release
 BuildRequires:  xf86-input-libinput
 %endif
 %endif
-%else
-%if 0%{?is_susecaasp}
-%if "%flavor" != "CAASP"
-ExclusiveArch:  do_not_build
-%endif
-%define theme CAASP
-%define product_nameX %{theme}-%{_target_cpu}
+
+%if "%theme" == "Kubic"
 %define branding_skelcd   CAASP
 %define branding_systemd  CAASP
+%define branding_plymouth openSUSE
+%define branding_grub2    openSUSE
+%define branding_gfxboot  openSUSE
+BuildRequires:  openSUSE-Kubic-release
+%ifnarch s390x
+BuildRequires:  xf86-input-libinput
+%endif
+%endif
+
+%if "%theme" == "SLED"
+%define branding_skelcd   SLED
+%define branding_systemd  SLE
 %define branding_plymouth SLE
 %define branding_grub2    SLE
 %define branding_gfxboot  SLE
-%define config_bootmenu_no_upgrade 1
-BuildRequires:  caasp-release
-BuildRequires:  caasp-release-DVD
-%else
-%if "%flavor" != "SLES" && "%flavor" != "SLED"
-ExclusiveArch:  do_not_build
+BuildRequires:  sled-release
+BuildRequires:  sled-release-DVD
+%if 0%{?sle_version} != 0150000
+BuildRequires:  sle12-desktop-migration
 %endif
-%if "%flavor" == "SLES"
-%define theme SLES
-%define product_nameX %{theme}-%{_target_cpu}
+%endif
+
+%if "%theme" == "SLES"
 %define branding_skelcd   SLES
 %define branding_systemd  SLE
 %define branding_plymouth SLE
@@ -103,27 +124,24 @@ BuildRequires:  sap-installation-wizard
 %endif
 %endif
 %endif
-%if "%flavor" == "SLED"
-# SLED is x86_64 only
-ExclusiveArch:  x86_64
-%define theme SLED
-%define product_nameX %{theme}-%{_target_cpu}
-%define branding_skelcd   SLED
-%define branding_systemd  SLE
+
+%if "%theme" == "CAASP"
+%define branding_skelcd   CAASP
+%define branding_systemd  CAASP
 %define branding_plymouth SLE
 %define branding_grub2    SLE
 %define branding_gfxboot  SLE
-BuildRequires:  sled-release
-BuildRequires:  sled-release-DVD
-%if 0%{?sle_version} != 0150000
-BuildRequires:  sle12-desktop-migration
-%endif
-%endif
-%endif
+%define config_bootmenu_no_upgrade 1
+BuildRequires:  caasp-release
+BuildRequires:  caasp-release-DVD
 %endif
 
+# ===  set product string (based on required packages)  ===
+
 %global product_name %(bash %_sourcedir/product_name)-%{_target_cpu}
 
+# ===  branding specific packages  ===
+
 BuildRequires:  skelcd-control-%branding_skelcd
 BuildRequires:  systemd-presets-branding-%branding_systemd
 %if %with_plymouth
@@ -135,6 +153,7 @@ BuildRequires:  gfxboot-branding-%branding_gfxboot
 %ifarch %ix86 x86_64 aarch64
 BuildRequires:  grub2-branding-%branding_grub2
 %endif
+
 # ===  branding end  ===
 
 # no i586 in Leap