diff --git a/CommonInstaller b/CommonInstaller
index 065d7f3..64755b1 100644
--- a/CommonInstaller
+++ b/CommonInstaller
@@ -256,7 +256,7 @@ mount_partitions () {
 		if [ -z ${SLOT} ]; then
 			SLOT=$(grep_cmdline androidboot.slot)
 			echo " INFO: #2 [SLOT] ${SLOT}"
-			if [ -n ${SLOT} ]; then
+			if [ ! -z ${SLOT} ]; then
 				SLOT=_${SLOT}
 				echo " INFO: #3 [SLOT] ${SLOT}"
 				DEVICE_AB=TRUE
diff --git a/patcher/CommonPatcher b/patcher/CommonPatcher
index 900b7a9..4525002 100644
--- a/patcher/CommonPatcher
+++ b/patcher/CommonPatcher
@@ -123,7 +123,7 @@ mount_partitions () {
 		if [ -z ${SLOT} ]; then
 			SLOT=$(grep_cmdline androidboot.slot)
 			echo " INFO: #2 [SLOT] ${SLOT}"
-			if [ -n ${SLOT} ]; then
+			if [ ! -z ${SLOT} ]; then
 				SLOT=_${SLOT}
 				echo " INFO: #3 [SLOT] ${SLOT}"
 				DEVICE_AB=TRUE
diff --git a/systest/SysTest b/systest/SysTest
index 6591b86..6e08988 100644
--- a/systest/SysTest
+++ b/systest/SysTest
@@ -111,7 +111,7 @@ mount_partitions () {
 	SLOT=$(grep_cmdline androidboot.slot_suffix)
 	if [ -z ${SLOT} ]; then
 		SLOT=$(grep_cmdline androidboot.slot)
-		if [ -n ${SLOT} ]; then
+		if [ ! -z ${SLOT} ]; then
 			SLOT=_${SLOT}
 			DEVICE_AB=TRUE
 		fi
diff --git a/uninstaller/META-INF/com/google/android/update-binary b/uninstaller/META-INF/com/google/android/update-binary
index d6742fc..e781042 100644
--- a/uninstaller/META-INF/com/google/android/update-binary
+++ b/uninstaller/META-INF/com/google/android/update-binary
@@ -139,7 +139,7 @@ mount_partitions () {
 		if [ -z ${SLOT} ]; then
 			SLOT=$(grep_cmdline androidboot.slot)
 			echo " INFO: #2 [SLOT] ${SLOT}"
-			if [ -n ${SLOT} ]; then
+			if [ ! -z ${SLOT} ]; then
 				SLOT=_${SLOT}
 				echo " INFO: #3 [SLOT] ${SLOT}"
 				DEVICE_AB=TRUE