diff --git a/grub-theme-openmamba-conf b/grub-theme-openmamba-conf
deleted file mode 100644
index 64fe0b4..0000000
--- a/grub-theme-openmamba-conf
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-
-cat << _EOF
-insmod png
-background_image /boot/grub/openmamba-grub-1024x768.png
-set color_normal=black/black
-set menu_color_normal=green/black
-set menu_color_highlight=white/green
-_EOF
diff --git a/grub-theme-openmamba.spec b/grub-theme-openmamba.spec
index fb04344..af86c34 100644
--- a/grub-theme-openmamba.spec
+++ b/grub-theme-openmamba.spec
@@ -1,47 +1,92 @@
 Name:          grub-theme-openmamba
 Version:       4.0
-Release:       1mamba
+Release:       3mamba
 Summary:       openmamba default theme for GRUB 2
-Group:         System/Kernel and Hardware
+Group:         Graphical Desktop/Look 'n' feel
 Vendor:        openmamba
 Distribution:  openmamba
 Packager:      Silvan Calarco <silvan.calarco@mambasoft.it>
-URL:           http://www.openmamba.org
-Source:        grub-theme-openmamba-conf
-Source1:       openmamba-grub-1024x768.png
+URL:           http://gitlab.mambasoft.it/openmamba/grub-theme-openmamba
+Source:        http://gitlab.mambasoft.it/openmamba/grub-theme-openmamba.git/%{version}/grub-theme-openmamba-%{version}.tar.bz2
 License:       GPL
 BuildRoot:     %{_tmppath}/%{name}-%{version}-root
 ## AUTOBUILDREQ-BEGIN
 ## AUTOBUILDREQ-END
 BuildArch:     noarch
 Requires(post): grub2
+Requires(post): breeze-grub >= 5.11.4-2mamba
 
 %description
 openmamba default theme for GRUB 2.
 
+%package circles
+Summary:       openmamba milestone4 default theme for GRUB 2
+Group:         Graphical Desktop/Look 'n' feel
+
+%description circles
+openmamba milestone4 default theme for GRUB 2.
+
 %prep
+%setup -q
 
 %build
 
 %install
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
-install -D -m0755 %{SOURCE0} %{buildroot}%{_sysconfdir}/grub.d/05_theme_openmamba
-install -D -m0644 %{SOURCE1} %{buildroot}/boot/grub/openmamba-grub-1024x768.png
+%makeinstall
 
 %clean
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
 
-%post
+%postun
+if [ $1 -eq 0 ]; then
+   sed -i "/^GRUB_THEME=\"%{_datadir}/grub/themes/breeze/theme.txt\"/d" /etc/default/grub
+fi
+:
+
+%posttrans
+if [ $1 -ge 1 ]; then
+   grep -q "^GRUB_THEME=" /etc/default/grub 2>/dev/null && continue
+   cat >> /etc/default/grub << _EOF
+GRUB_THEME="%{_datadir}/grub/themes/breeze/theme.txt"
+_EOF
+fi
 [ -x %{_sbindir}/update-grub -a -e /boot/grub/grub.cfg ] && \
    %{_sbindir}/update-grub
-exit 0
+:
+
+%postun circles
+if [ $1 -eq 0 ]; then
+   sed -i "/^GRUB_THEME=\"%{_datadir}/grub/themes/circles/theme.txt\"/d" /etc/default/grub
+fi
+:
+
+%posttrans circles
+if [ $1 -ge 1 ]; then
+   grep -q "^GRUB_THEME=" /etc/default/grub 2>/dev/null && continue
+   cat >> /etc/default/grub << _EOF
+GRUB_THEME="%{_datadir}/grub/themes/circles/theme.txt"
+_EOF
+fi
+[ -x %{_sbindir}/update-grub -a -e /boot/grub/grub.cfg ] && \
+   %{_sbindir}/update-grub
+:
 
 %files
 %defattr(-,root,root)
-%{_sysconfdir}/grub.d/05_theme_openmamba
-/boot/grub/openmamba-grub-1024x768.png
+
+%files circles
+%defattr(-,root,root)
+%dir %{_datadir}/grub/themes/circles
+%{_datadir}/grub/themes/circles/*
 
 %changelog
+* Sun Dec 17 2017 Silvan Calarco <silvan.calarco@mambasoft.it> 4.0-3mamba
+- switch to breeze as default transitory theme for next milestone
+
+* Sun Dec 17 2017 Silvan Calarco <silvan.calarco@mambasoft.it> 4.0-2mamba
+- reworked as a standard grub2 theme installable by setting GRUB_THEME in /etc/default/grub
+
 * Thu Aug 25 2016 Silvan Calarco <silvan.calarco@mambasoft.it> 4.0-1mamba
 - update to 4.0
 - new grub theme for openmamba milestone4
diff --git a/openmamba-grub-1024x768.png b/openmamba-grub-1024x768.png
deleted file mode 100644
index 98548c7..0000000
Binary files a/openmamba-grub-1024x768.png and /dev/null differ