diff --git a/vpnor/test/write_patch_resize.cpp b/vpnor/test/write_patch_resize.cpp
new file mode 100644
index 0000000..8d67683
--- /dev/null
+++ b/vpnor/test/write_patch_resize.cpp
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2018 IBM Corp.
+
+#include <assert.h>
+#include <experimental/filesystem>
+#include <fcntl.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/syslog.h>
+#include <unistd.h>
+
+#include "config.h"
+#include "common.h"
+#include "mbox.h"
+#include "mboxd_flash.h"
+
+#include "vpnor/test/tmpd.hpp"
+
+static constexpr auto BLOCK_SIZE = 0x1000;
+static constexpr auto PART_SIZE = BLOCK_SIZE;
+static constexpr auto PATCH_SIZE = BLOCK_SIZE / 2;
+static constexpr auto UPDATE_SIZE = BLOCK_SIZE;
+
+const std::string toc[] = {
+    "partition01=TEST1,00001000,00002000,80,ECC,READWRITE",
+};
+
+int main(void)
+{
+    namespace fs = std::experimental::filesystem;
+    namespace test = openpower::virtual_pnor::test;
+
+    struct mbox_context _ctx, *ctx = &_ctx;
+    void *map;
+    int rc;
+    int fd;
+
+    /* Setup */
+    memset(ctx, 0, sizeof(mbox_context));
+
+    mbox_vlog = &mbox_log_console;
+    verbosity = (verbose)2;
+
+    test::VpnorRoot root(ctx, toc, BLOCK_SIZE);
+    std::vector<uint8_t> roContent(PART_SIZE, 0xff);
+    root.write("TEST1", roContent.data(), roContent.size());
+    /* write_flash doesn't copy the file for us */
+    std::vector<uint8_t> patchContent(PATCH_SIZE, 0xaa);
+    root.patch("TEST1", patchContent.data(), patchContent.size());
+
+    init_vpnor_from_paths(ctx);
+
+    /* Test */
+    std::vector<uint8_t> update(UPDATE_SIZE, 0x55);
+    rc = write_flash(ctx, 0x1000, update.data(), update.size());
+    assert(rc == 0);
+
+    /* Check that PATCH is modified with the new data */
+    fs::path patch = root.patch() / "TEST1";
+    assert(UPDATE_SIZE == fs::file_size(patch));
+    fd = open(patch.c_str(), O_RDONLY);
+    map = mmap(NULL, UPDATE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
+    assert(map != MAP_FAILED);
+    rc = memcmp(update.data(), map, update.size());
+    assert(rc == 0);
+    munmap(map, update.size());
+    close(fd);
+
+    destroy_vpnor(ctx);
+    free(ctx->flash_bmap);
+
+    return rc;
+}