diff --git a/build/ext_mapping.conf.json b/build/ext_mapping.conf.json
index 83b589c758..8d93b8ce36 100644
--- a/build/ext_mapping.conf.json
+++ b/build/ext_mapping.conf.json
@@ -8,7 +8,8 @@
         "2326530962": "https://storage.nemax.nebius.cloud/nbs-oss-resources/fio-static.tgz",
         "4449551218": "https://storage.nemax.nebius.cloud/nbs-oss-resources/qemu-static.tgz",
         "3307630510": "https://storage.nemax.nebius.cloud/nbs-oss-resources/rootfs.img",
-        "4556399018": "https://storage.nemax.nebius.cloud/nbs-oss-resources/virtiofs-server"
+        "4556399018": "https://storage.nemax.nebius.cloud/nbs-oss-resources/virtiofs-server",
+        "2513045473": "https://storage.nemax.nebius.cloud/nbs-oss-resources/flock"
     },
     "resources_descriptions": {
         "4081472014": "cloud/blockstore/tests/loadtest/selftest",
@@ -18,7 +19,8 @@
         "2326530962": "cloud/storage/core/tools/testing/fio/bin",
         "4449551218": "cloud/storage/core/tools/testing/qemu/bin",
         "3307630510": "cloud/storage/core/tools/testing/qemu/image",
-        "4556399018": "cloud/storage/core/tools/testing/virtiofs_server/bin"
+        "4556399018": "cloud/storage/core/tools/testing/virtiofs_server/bin",
+        "2513045473": "flock from util-linux 2.37.370-30ec"
     },
     "tasks": {}
 }