diff --git a/recipes-core/images/security-test-image.bb b/recipes-core/images/security-test-image.bb
index babe3fd..54d8978 100644
--- a/recipes-core/images/security-test-image.bb
+++ b/recipes-core/images/security-test-image.bb
@@ -8,4 +8,11 @@ TEST_SUITES = "ssh ping ptest apparmor clamav samhain sssd tripwire checksec sma
 
 INSTALL_CLAMAV_CVD = "1"
 
-IMAGE_ROOTFS_EXTRA_SPACE = "5242880"
+IMAGE_OVERHEAD_FACTOR = "1.0"
+IMAGE_ROOTFS_EXTRA_SPACE = "1124288"
+
+# ptests need more memory than standard to avoid the OOM killer
+# also lttng-tools needs /tmp that has at least 1G
+QB_MEM = "-m 2048"
+
+PTEST_EXPECT_FAILURE = "1"