diff --git a/xCAT-server/share/xcat/install/ubuntu/compute.tmpl b/xCAT-server/share/xcat/install/ubuntu/compute.tmpl
index d2ec827a0..adcfab038 100644
--- a/xCAT-server/share/xcat/install/ubuntu/compute.tmpl
+++ b/xCAT-server/share/xcat/install/ubuntu/compute.tmpl
@@ -38,7 +38,9 @@ d-i partman-md/device_remove_md boolean true
 #create the /tmp/partitioning based on the uefi or legacy bios 
 d-i partman/early_command string \
     set -x; \
-    DEV=`ls /dev/disk/by-path/* -l | egrep -o '/dev.*sd[^0-9]$' | sort | head -n1 | egrep -o 'sd.*$'`; echo "/dev/$DEV" > /tmp/boot_disk; \
+    DEV=`ls /dev/disk/by-path/* -l | egrep -o '/dev.*sd[^0-9]$' | sort -t : -k 1 -k 2 -k 3 -k 4 -k 5 -k 6 -k 7 -k 8 -g | head -n1 | egrep -o 'sd.*$'`; \
+    if [[ $DEV == "" ]]; then DEV="sda"; fi; \
+    echo "/dev/$DEV" > /tmp/boot_disk; \
     debconf-set partman-auto/disk "$(cat /tmp/boot_disk)"
 d-i partman-auto/expert_recipe_file string /tmp/partitioning