diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index d32090a..9612499 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -431,6 +431,9 @@
           size = common.RoundUpTo4K(size)
         else:
           size = ((size + block_size - 1) // block_size) * block_size
+        # Use a minimum size, otherwise we will fail to calculate an AVB footer
+        # or fail to construct an ext4 image.
+        size = max(size, 256 * 1024)
       extfs_inode_count = prop_dict["extfs_inode_count"]
       inodes = int(fs_dict.get("Inode count", extfs_inode_count))
       inodes -= int(fs_dict.get("Free inodes", "0"))