diff --git a/usr/share/archboot/installer/setup b/usr/share/archboot/installer/setup
index 3d72010eb..e89d7c049 100755
--- a/usr/share/archboot/installer/setup
+++ b/usr/share/archboot/installer/setup
@@ -21,6 +21,9 @@ FILE_URL="file:///src/core-$(uname -m)/pkg"
 MIRRORLIST="/etc/pacman.d/mirrorlist"
 PACKAGES=
 
+# destination of blockdevices in /sys
+block=/sys/block
+
 # partitions
 PART_ROOT=
 ROOTFS=""
@@ -106,7 +109,6 @@ check_media() {
 
 # Get cdroms and removable devices
 get_media() {
-    block=/sys/block
     media=/src
     SET_MEDIA=0
     #unmount media first, we may have leftovers ...
@@ -149,7 +151,6 @@ manual_media() {
 }
 
 finddisks() {
-    block=/sys/block
     # ide devices
     for dev in $(ls $block | egrep '^hd'); do
         if [ "$(cat $block/$dev/device/media)" = "disk" ]; then
@@ -191,7 +192,6 @@ finddisks() {
 
 # don't check on raid devices!
 findbootloaderdisks() {
-    block=/sys/block
     # ide devices
     for dev in $(ls $block | egrep '^hd'); do
         if [ "$(cat $block/$dev/device/media)" = "disk" ]; then
@@ -227,12 +227,19 @@ findbootloaderdisks() {
 }
 
 findpartitions() {
-    block=/sys/block
     for devpath in $(finddisks); do
-        disk=$(echo $devpath | sed 's|.*/||')
+        disk=$(basename $devpath)
         for part in $(ls $block/$disk | egrep ^$disk); do
-            # check if not already assembled to a none partitionable raid device, includes also partitionable raid partitions
-            if ! [ "$(cat /proc/mdstat 2>/dev/null | grep $part)" -o "$(fstype 2>/dev/null </dev/$part | grep "lvm2")" -o "$(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk##g") 2>/dev/null | grep "5")" ]; then
+            # exclude checks:
+            #- part of raid device
+            #  $(cat /proc/mdstat 2>/dev/null | grep $part)
+            #- part of lvm2 device
+            #  $(fstype 2>/dev/null </dev/$part | grep "lvm2")
+            #- extended partition
+            #  $(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk##g") 2>/dev/null | grep "5")
+            #- extended partition on raid partition device
+            #  $(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk\p##g" 2>/dev/null | grep "5")
+            if ! [ "$(cat /proc/mdstat 2>/dev/null | grep $part)" -o "$(fstype 2>/dev/null </dev/$part | grep "lvm2")" -o "$(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk##g") 2>/dev/null | grep "5")" -o "$(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk\p##g") 2>/dev/null | grep "5")" ]; then
                 if [ -d $block/$disk/$part ]; then
                     echo "/dev/$part"
                     [ "$1" ] && echo $1
@@ -268,13 +275,20 @@ findpartitions() {
     fi
 }
 
-# don't list raid devices!
+# don't list raid devices, lvm2 and devicemapper!
 findbootloaderpartitions() {
-    block=/sys/block
     for devpath in $(finddisks); do
-        disk=$(echo $devpath | sed 's|.*/||')
+        disk=$(basename $devpath)
         for part in $(ls $block/$disk | egrep ^$disk); do
-            # check if not already assembled to a raid device
+            # exclude checks:
+            #- part of raid device
+            #  $(cat /proc/mdstat 2>/dev/null | grep $part)
+            #- part of lvm2 device
+            #  $(fstype 2>/dev/null </dev/$part | grep "lvm2")
+            #- extended partition
+            #  $(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk##g") 2>/dev/null | grep "5")
+            #- partitionable raid partition
+            #  $(echo $part | grep md_d[0-9])
             if ! [ "$(cat /proc/mdstat 2>/dev/null | grep $part)" -o "$(fstype 2>/dev/null </dev/$part | grep "lvm2")" -o "$(sfdisk -c /dev/$disk $(echo $part | sed -e "s#$disk##g") 2>/dev/null | grep "5")" -o "$(echo $part | grep md_d[0-9])" ]; then
                 if [ -d $block/$disk/$part ]; then
                     echo "/dev/$part"
@@ -655,7 +669,7 @@ storage is duplication." 0 0
     SPARE_DEVICES="$(cat /tmp/.raid-spare | wc -l)"
     # generate options for mdadm
     RAIDOPTIONS="--force --run --level=$LEVEL"
-    [ "$(echo $RAIDDEVICE | grep /md_d[0-9])" ] && RAIDOPTIONS="$RAIDOPTIONS -a mdp"
+    [ "$(echo $RAIDDEVICE | grep /md_d[0-9])" ] && RAIDOPTIONS="$RAIDOPTIONS -a mdp" && modprobe md_mod 2>/dev/null
     ! [ "$RAID_DEVICES" = "0" ] && RAIDOPTIONS="$RAIDOPTIONS --raid-devices=$RAID_DEVICES"
     ! [ "$SPARE_DEVICES" = "0" ] && RAIDOPTIONS="$RAIDOPTIONS --spare-devices=$SPARE_DEVICES"
     ! [ "$PARITY" = "" ] && RAIDOPTIONS="$RAIDOPTIONS --layout=$PARITY"
@@ -671,7 +685,7 @@ storage is duplication." 0 0
     fi
     # writing raid information to partition table
     if [ "$(echo $RAIDDEVICE | grep /md_d[0-9])" ]; then
-        for i in $(sfdisk -l $RAIDDEVICE | grep ^/dev | grep -v Empty | sed -e 's# .*##g'); do
+        for i in $(sfdisk -l $RAIDDEVICE | grep ^/dev | grep -v Empty | grep -v Extended | sed -e 's# .*##g'); do
             # get device name
             k=$(echo $i | sed -e 's#p[0-9]##g')
             # get partition number of device