diff --git a/src/disk_tool/disk_tool_prepare.cpp b/src/disk_tool/disk_tool_prepare.cpp
index b4219d0d..ea20f7a7 100644
--- a/src/disk_tool/disk_tool_prepare.cpp
+++ b/src/disk_tool/disk_tool_prepare.cpp
@@ -149,9 +149,12 @@ int disk_tool_t::prepare_one(std::map<std::string, std::string> options, int is_
     {
         if (options["block_size"] == "")
             options["block_size"] = "1M";
+        if (is_hybrid && options["atomic_write_size"] == "")
+            options["atomic_write_size"] = "0";
         if (is_hybrid && options["throttle_small_writes"] == "")
             options["throttle_small_writes"] = "1";
-        if (!is_hybrid && options.find("data_csum_type") != options.end() && options.at("data_csum_type") != "")
+        if (!is_hybrid && options.find("data_csum_type") != options.end() && options.at("data_csum_type") != "" &&
+            options["csum_block_size"] == "")
             options["csum_block_size"] = "32k";
     }
     else if (!json_is_true(options["disable_data_fsync"]))