diff --git a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat
index c1bfd7c5c..ff5af4262 100644
--- a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat
+++ b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat
@@ -33,6 +33,7 @@ check:rc==0
 cmd:if [ ! -d /tmp/mountoutput ]; then mkdir -p /tmp/mountoutput; fi
 cmd:mount |sort > /tmp/mountoutput/file.org
 cmd:cat /tmp/mountoutput/file.org
+cmd:if [[ "__GETNODEATTR($$CN,os)__" =~ "ubuntu16.04.5" ]]; then chdef -t osimage -o __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute  -p pkgdir="http://archive.ubuntu.com/ubuntu xenial universe main,http://archive.ubuntu.com/ubuntu xenial-updates universe main,http://security.ubuntu.com/ubuntu xenial-security main restricted";fi
 cmd:genimage  __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute
 check:rc==0
 cmd:mount |sort > /tmp/mountoutput/file.new
diff --git a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat_postscripts_failed b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat_postscripts_failed
index 1b0d15691..08f8b0716 100644
--- a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat_postscripts_failed
+++ b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_flat_postscripts_failed
@@ -37,6 +37,7 @@ check:rc==0
 cmd:if [ ! -d /tmp/mountoutput ]; then mkdir -p /tmp/mountoutput; fi
 cmd:mount |sort > /tmp/mountoutput/file.org
 cmd:cat /tmp/mountoutput/file.org
+cmd:if [[ "__GETNODEATTR($$CN,os)__" =~ "ubuntu16.04.5" ]]; then chdef -t osimage -o __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute  -p pkgdir="http://archive.ubuntu.com/ubuntu xenial universe main,http://archive.ubuntu.com/ubuntu xenial-updates universe main,http://security.ubuntu.com/ubuntu xenial-security main restricted";fi
 cmd:genimage  __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute
 check:rc==0
 cmd:mount |sort > /tmp/mountoutput/file.new
diff --git a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_hierarchy b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_hierarchy
index b24aafdd1..b33bd429c 100644
--- a/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_hierarchy
+++ b/xCAT-test/autotest/testcase/installation/reg_linux_diskless_installation_hierarchy
@@ -37,6 +37,7 @@ check:rc==0
 cmd:if [[ -f /test.synclist ]] ;then mv -f /test.synclist /test.synclist.bak;fi;
 cmd:echo "/test.synclist -> /test.synclist" > /test.synclist;chdef -t osimage -o __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute synclists=/test.synclist
 check:rc==0
+cmd:if [[ "__GETNODEATTR($$CN,os)__" =~ "ubuntu16.04.5" ]]; then chdef -t osimage -o __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute  -p pkgdir="http://archive.ubuntu.com/ubuntu xenial universe main,http://archive.ubuntu.com/ubuntu xenial-updates universe main,http://security.ubuntu.com/ubuntu xenial-security main restricted";fi
 cmd:genimage  __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute
 check:rc==0
 cmd:packimage __GETNODEATTR($$CN,os)__-__GETNODEATTR($$CN,arch)__-netboot-compute