diff --git a/README.md b/README.md
index bc24864..8e3b70f 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ Files from `/etc/skel` are copied to `/home/$USER` when new users are created.
 
 Example: [pkg/de-p1st-gnupg/PKGBUILD](pkg/de-p1st-gnupg/PKGBUILD)
 
-### enabling services
+### Enabling services
 
 * systemd.preset - Service enablement presets
 * [man 5 systemd.preset](https://www.systutorials.com/docs/linux/man/5-systemd.preset/)
diff --git a/build-archiso.sh b/build-archiso.sh
index 72a8366..950052a 100755
--- a/build-archiso.sh
+++ b/build-archiso.sh
@@ -12,7 +12,7 @@
 # -> git
 #
 BUILD_DIR=./archlive
-PKGS=('git' 'de-p1st-keyboard' 'de-p1st-nano' 'de-p1st-pacman' 'de-p1st-pacman-mirrorlist' 'de-p1st-systemd')
+PKGS=('git' 'de-p1st-keyboard' 'de-p1st-nano' 'de-p1st-pacman' 'de-p1st-systemd')
 PACMAN_CFG_ADDITION='pkg/de-p1st-pacman/pacman.d/de-p1st' # will be used to extend the builder's pacman.conf
 
 
diff --git a/pkg/de-p1st-installer/de-p1st-installer.sh b/pkg/de-p1st-installer/de-p1st-installer.sh
index 74bac6b..2cd48cd 100755
--- a/pkg/de-p1st-installer/de-p1st-installer.sh
+++ b/pkg/de-p1st-installer/de-p1st-installer.sh
@@ -125,7 +125,7 @@ function get_default_mount_options() {
 
 function choose_mount_options() {
   # return: the following variables:
-  #   FS_MOUNT_OPTIONS (array)
+  #   FS_CHOSEN_MOUNT_OPTIONS (array)
 
   case "${FS}" in
 	BTRFS)
@@ -149,7 +149,7 @@ function choose_mount_options() {
 		;;
   esac
 
-  get_multi_choice  FS_MOUNT_OPTIONS "Select mount options" TMP1 || return $?
+  get_multi_choice  FS_CHOSEN_MOUNT_OPTIONS "Select mount options" TMP1 || return $?
 }
 
 function main() {
@@ -163,15 +163,30 @@ function main() {
   partition "${TARGET_BLOCK_DEVICE}" "$BIOS_TYPE" || return $?
   format "$BIOS_TYPE" "${BOOT_PART}" "${LUKS_PART}" "${LUKS_PWD}" "${FS}" DATA_PART || return $?
 
-  # TODO: use FS_DEFAULT_MOUNT_OPTIONS and FS_MOUNT_OPTIONS in combination
-  mount "$DATA_PART" /mnt || return $?
-  mkdir /mnt/boot && mount "$BOOT_PART" /mnt/boot || return $?
+  # Combine default and chosen mount options
+  TMP1=("${FS_DEFAULT_MOUNT_OPTIONS[@]}" "${FS_CHOSEN_MOUNT_OPTIONS[@]}") || return $?
+  # Join array elements by ","
+  join_by "," TMP1 FS_MOUNT_OPTIONS || return $?
+  echo "Mounting data partition with options: ${FS_MOUNT_OPTIONS}"
+  mount -o "${FS_MOUNT_OPTIONS}" "$DATA_PART" /mnt || return $?
+  # mount boot partition
+  mkdir /mnt/boot              || return $?
+  mount "$BOOT_PART" /mnt/boot || return $?
 
+  case "${BIOS_TYPE}" in
+  uefi)
+    pacstrap /mnt "${KERNEL}" "${KERNEL}-headers" de-p1st-base-efi || return $?
+    ;;
+  bios)
+    echo "Not yet implemented"
+    return 1
+    ;;
+  *)
+    echo "Not yet implemented!"
+    return 1
+    ;;
+  esac
 
-  # TODO: testing
-  #   if bios type is bios then ... :/
-  #   amd/intel-ucode
-  pacstrap /mnt "${KERNEL}" "${KERNEL}-headers" de-p1st-base-efi
 }
 
 main "$@"
diff --git a/pkg/de-p1st-installer/installer.cfg b/pkg/de-p1st-installer/installer.cfg
index 6aa3cd4..e089042 100644
--- a/pkg/de-p1st-installer/installer.cfg
+++ b/pkg/de-p1st-installer/installer.cfg
@@ -11,7 +11,7 @@ KERNEL=linux
 TARGET_BLOCK_DEVICE=/dev/sda
 BOOT_PART_SIZE=500  # MiB
 FS=BTRFS
-FS_MOUNT_OPTIONS=('noatime')
+FS_CHOSEN_MOUNT_OPTIONS=('noatime')
 
 CPU_VENDOR=none
 BIOS_TYPE=uefi
diff --git a/pkg/de-p1st-installer/lib/util.sh b/pkg/de-p1st-installer/lib/util.sh
index c7a3711..9feefeb 100644
--- a/pkg/de-p1st-installer/lib/util.sh
+++ b/pkg/de-p1st-installer/lib/util.sh
@@ -1,3 +1,15 @@
+function join_by() {
+  # Join array elements with character $1
+  # $1: delimiter
+  # $2: name of source array
+  # $3: variable name to store result
+
+  local -n ptr=$2  || return $?
+  local -n ptr2=$3 || return $?
+  ptr2=$(printf ",%s" "${ptr[@]}")
+  ptr2=${ptr2:1}
+}
+
 function newline_to_space() {
   # Replaces all newlines with spaces
   # $1: name of variable