diff --git a/tools/xen/functions b/tools/xen/functions
index 7616a5fd4d..a5c4b70bc3 100644
--- a/tools/xen/functions
+++ b/tools/xen/functions
@@ -268,3 +268,22 @@ function attach_network() {
 
     xe network-attach uuid=$net host-uuid=$host
 }
+
+function set_vm_memory() {
+    local vm_name_label
+    local memory
+
+    vm_name_label="$1"
+    memory="$2"
+
+    local vm
+
+    vm=$(_vm_uuid "$vm_name_label")
+
+    xe vm-memory-limits-set \
+        static-min=${memory}MiB \
+        static-max=${memory}MiB \
+        dynamic-min=${memory}MiB \
+        dynamic-max=${memory}MiB \
+        uuid=$vm
+}
diff --git a/tools/xen/install_os_domU.sh b/tools/xen/install_os_domU.sh
index a012a08561..b49504d9e9 100755
--- a/tools/xen/install_os_domU.sh
+++ b/tools/xen/install_os_domU.sh
@@ -228,8 +228,11 @@ if [ -z "$templateuuid" ]; then
     $THIS_DIR/scripts/install-os-vpx.sh \
         -t "$UBUNTU_INST_TEMPLATE_NAME" \
         -n "$UBUNTU_INST_BRIDGE_OR_NET_NAME" \
-        -l "$GUEST_NAME" \
-        -r "$OSDOMU_MEM_MB"
+        -l "$GUEST_NAME"
+
+    set_vm_memory "$GUEST_NAME" "$OSDOMU_MEM_MB"
+
+    xe vm-start vm="$GUEST_NAME"
 
     # wait for install to finish
     wait_for_VM_to_halt
@@ -255,6 +258,9 @@ fi
 # Install XenServer tools, and other such things
 $THIS_DIR/prepare_guest_template.sh "$GUEST_NAME"
 
+# Set virtual machine parameters
+set_vm_memory "$GUEST_NAME" "$OSDOMU_MEM_MB"
+
 # start the VM to run the prepare steps
 xe vm-start vm="$GUEST_NAME"
 
diff --git a/tools/xen/scripts/install-os-vpx.sh b/tools/xen/scripts/install-os-vpx.sh
index 8ee8b675a9..c94a593e3d 100755
--- a/tools/xen/scripts/install-os-vpx.sh
+++ b/tools/xen/scripts/install-os-vpx.sh
@@ -20,8 +20,6 @@
 set -eux
 
 BRIDGE=
-RAM=
-BALLOONING=
 NAME_LABEL=
 TEMPLATE_NAME=
 
@@ -29,7 +27,7 @@ usage()
 {
 cat << EOF
 
-  Usage: $0 -t TEMPLATE_NW_INSTALL -l NAME_LABEL [-n BRIDGE] [-r RAM] [-b] 
+  Usage: $0 -t TEMPLATE_NW_INSTALL -l NAME_LABEL [-n BRIDGE]
 
   Install a VM from a template
 
@@ -37,9 +35,6 @@ cat << EOF
 
      -h           Shows this message.
      -t template  VM template to use
-     -b           Enable memory ballooning. When set min_RAM=RAM/2 max_RAM=RAM.
-     -r MiB       Specifies RAM used by the VPX, in MiB.
-                  By default it will take the value from the XVA.
      -l name      Specifies the name label for the VM.
      -n bridge    The bridge/network to use for eth0. Defaults to xenbr0
 EOF
@@ -53,12 +48,6 @@ get_params()
       h) usage
          exit 1
          ;;
-      b)
-         BALLOONING=1
-         ;;
-      r)
-         RAM=$OPTARG
-         ;;
       n)
          BRIDGE=$OPTARG
          ;;
@@ -119,19 +108,6 @@ create_vif()
 }
 
 
-set_memory()
-{
-  local v="$1"
-  if [ "$RAM" != "" ]
-  then
-    echo "Setting RAM to $RAM MiB."
-    [ "$BALLOONING" == 1 ] && RAM_MIN=$(($RAM / 2)) || RAM_MIN=$RAM
-    xe vm-memory-limits-set static-min=16MiB static-max=${RAM}MiB \
-                            dynamic-min=${RAM_MIN}MiB dynamic-max=${RAM}MiB \
-                            uuid="$v"
-  fi
-}
-
 
 # Make the VM auto-start on server boot.
 set_auto_start()
@@ -161,5 +137,3 @@ set_auto_start "$vm_uuid"
 create_vif "$vm_uuid"
 xe vm-param-set other-config:os-vpx=true uuid="$vm_uuid"
 xe vm-param-set actions-after-reboot=Destroy uuid="$vm_uuid"
-set_memory "$vm_uuid"
-xe vm-start uuid=$vm_uuid