diff --git a/flang/runtime/buffer.h b/flang/runtime/buffer.h
--- a/flang/runtime/buffer.h
+++ b/flang/runtime/buffer.h
@@ -94,7 +94,7 @@
         start_ + (at - fileOffset_) + static_cast<std::int64_t>(bytes) >
             size_) {
       Flush(handler);
-      fileOffset_ = at;
+      Reset(at);
       Reallocate(bytes, handler);
     }
     dirty_ = true;
diff --git a/flang/runtime/io-api.cpp b/flang/runtime/io-api.cpp
--- a/flang/runtime/io-api.cpp
+++ b/flang/runtime/io-api.cpp
@@ -517,7 +517,7 @@
   }
   connection.currentRecordNumber = rec;
   if (auto *unit{io.GetExternalFileUnit()}) {
-    unit->SetPosition(rec * *connection.recordLength);
+    unit->SetPosition((rec - 1) * *connection.recordLength);
   }
   return true;
 }