diff --git a/support/testing/tests/fs/test_ext.py b/support/testing/tests/fs/test_ext.py
index 34321a3995..0832ba4ce2 100644
--- a/support/testing/tests/fs/test_ext.py
+++ b/support/testing/tests/fs/test_ext.py
@@ -97,7 +97,7 @@ class TestExt4(infra.basetest.BRTest):
 """
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
-BR2_TARGET_ROOTFS_EXT2_BLOCKS=16384
+BR2_TARGET_ROOTFS_EXT2_SIZE="16384"
 BR2_TARGET_ROOTFS_EXT2_INODES=3000
 BR2_TARGET_ROOTFS_EXT2_RESBLKS=10
 # BR2_TARGET_ROOTFS_TAR is not set