diff --git a/poky/scripts/autobuilder-worker-prereq-tests b/poky/scripts/autobuilder-worker-prereq-tests
index 82e9a77..572227d 100755
--- a/poky/scripts/autobuilder-worker-prereq-tests
+++ b/poky/scripts/autobuilder-worker-prereq-tests
@@ -51,16 +51,31 @@
     echo 'Need to increase watches (echo fs.inotify.max_user_watches=65536 | sudo tee -a /etc/sysctl.conf'
     exit 1
 fi
+OPEN_FILES=$(ulimit -n)
+if (( $OPEN_FILES < 65535 )); then
+    echo 'Increase maximum open files in /etc/security/limits.conf'
+    echo '*            soft    nofile           131072'
+    echo '*            hard    nofile           131072'
+    exit 1
+fi
+MAX_PROCESSES=$(ulimit -u)
+if (( $MAX_PROCESSES < 514542 )); then
+    echo 'Increase maximum user processes in /etc/security/limits.conf'
+    echo '*            hard    nproc           515294'
+    echo '*            soft    nproc           514543'
+    exit 1
+fi
+
 mkdir -p tmp/deploy/images/qemux86-64
 pushd tmp/deploy/images/qemux86-64
 if [ ! -e core-image-minimal-qemux86-64.ext4 ]; then
-    wget http://downloads.yoctoproject.org/releases/yocto/yocto-2.5.1/machines/qemu/qemux86-64/core-image-minimal-qemux86-64.ext4
+    wget http://downloads.yoctoproject.org/releases/yocto/yocto-4.0/machines/qemu/qemux86-64/core-image-minimal-qemux86-64.ext4
 fi
 if [ ! -e core-image-minimal-qemux86-64.qemuboot.conf ]; then
-    wget http://downloads.yoctoproject.org/releases/yocto/yocto-2.5.1/machines/qemu/qemux86-64/core-image-minimal-qemux86-64.qemuboot.conf
+    wget http://downloads.yoctoproject.org/releases/yocto/yocto-4.0/machines/qemu/qemux86-64/core-image-minimal-qemux86-64.qemuboot.conf
 fi
 if [ ! -e bzImage-qemux86-64.bin ]; then
-    wget http://downloads.yoctoproject.org/releases/yocto/yocto-2.5.1/machines/qemu/qemux86-64/bzImage-qemux86-64.bin
+    wget http://downloads.yoctoproject.org/releases/yocto/yocto-4.0/machines/qemu/qemux86-64/bzImage-qemux86-64.bin
 fi
 popd
 bitbake qemu-helper-native