diff --git a/system/update_engine/payload_generator/generate_delta_main.cc b/system/update_engine/payload_generator/generate_delta_main.cc
index 6616ee1c9f9..6861705b58e 100644
--- a/system/update_engine/payload_generator/generate_delta_main.cc
+++ b/system/update_engine/payload_generator/generate_delta_main.cc
@@ -465,7 +465,7 @@ void RoundDownPartitions(const ImageConfig& config) {
     if (part.path.empty()) {
       continue;
     }
-    const auto size = utils::FileSize(part.path);
+    const auto size = std::max<size_t>(utils::FileSize(part.path), kBlockSize);
     if (size % kBlockSize != 0) {
       const auto err =
           truncate(part.path.c_str(), size / kBlockSize * kBlockSize);