diff --git a/frameworks/utest/source/shim.cpp b/frameworks/utest/source/shim.cpp
new file mode 100644
index 0000000000..4065a16516
--- /dev/null
+++ b/frameworks/utest/source/shim.cpp
@@ -0,0 +1,138 @@
+/****************************************************************************
+ * Copyright (c) 2015, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ ****************************************************************************
+ */
+
+#include "utest/shim.h"
+
+#if UTEST_SHIM_SCHEDULER_USE_MINAR
+#include "minar/minar.h"
+
+static int32_t utest_minar_init()
+{
+    return 0;
+}
+static void *utest_minar_post(const utest_v1_harness_callback_t callback, const uint32_t delay_ms)
+{
+    void *handle = minar::Scheduler::postCallback(callback).delay(minar::milliseconds(delay_ms)).getHandle();
+    return handle;
+}
+static int32_t utest_minar_cancel(void *handle)
+{
+    int32_t ret = minar::Scheduler::cancelCallback(handle);
+    return ret;
+}
+static int32_t utest_minar_run()
+{
+    return 0;
+}
+extern "C" {
+static const utest_v1_scheduler_t utest_v1_scheduler =
+{
+    utest_minar_init,
+    utest_minar_post,
+    utest_minar_cancel,
+    utest_minar_run
+};
+utest_v1_scheduler_t utest_v1_get_scheduler()
+{
+    return utest_v1_scheduler;
+}
+}
+
+#elif UTEST_SHIM_SCHEDULER_USE_US_TICKER
+#ifdef YOTTA_MBED_HAL_VERSION_STRING
+#   include "mbed-hal/us_ticker_api.h"
+#else
+#   include "us_ticker_api.h"
+#endif
+// only one callback is active at any given time
+static volatile utest_v1_harness_callback_t minimal_callback;
+static volatile utest_v1_harness_callback_t ticker_callback;
+static const ticker_data_t *ticker_data;
+static ticker_event_t ticker_event;
+
+static void ticker_handler(uint32_t)
+{
+    // printf("\t\t>>> Ticker callback fired for %p.\n", ticker_callback);
+    minimal_callback = ticker_callback;
+}
+
+static int32_t utest_us_ticker_init()
+{
+    ticker_data = get_us_ticker_data();
+    ticker_set_handler(ticker_data, ticker_handler);
+    return 0;
+}
+static void *utest_us_ticker_post(const utest_v1_harness_callback_t callback, const uint32_t delay_ms)
+{
+    // printf("\t\t>>> Schedule %p with %ums delay => %p.\n", callback, (unsigned int)delay_ms, (void*)1);
+    if (delay_ms) {
+        ticker_callback = callback;
+        // fire the interrupt in 1000us * delay_ms
+        ticker_insert_event(ticker_data, &ticker_event, ticker_read(ticker_data) + delay_ms * 1000, 0);
+    } else {
+        minimal_callback = callback;
+    }
+
+    // return a bogus handle
+    return (void*)1;
+}
+static int32_t utest_us_ticker_cancel(void *handle)
+{
+    // printf("\t\t>>> Cancel %p => %u\n", handle, (unsigned int)0);
+    (void) handle;
+    ticker_remove_event(ticker_data, &ticker_event);
+    return 0;
+}
+static int32_t utest_us_ticker_run()
+{
+    while(1)
+    {
+        // check if a new callback has been set
+        if (minimal_callback)
+        {
+            // printf("\t\t>>> Firing callback %p\n", minimal_callback);
+            // copy the callback
+            utest_v1_harness_callback_t callback = minimal_callback;
+            // reset the shared callback
+            minimal_callback = NULL;
+            // execute the copied callback
+            callback();
+        }
+    }
+    return 0;
+}
+extern "C" {
+static const utest_v1_scheduler_t utest_v1_scheduler =
+{
+    utest_us_ticker_init,
+    utest_us_ticker_post,
+    utest_us_ticker_cancel,
+    utest_us_ticker_run
+};
+utest_v1_scheduler_t utest_v1_get_scheduler()
+{
+    return utest_v1_scheduler;
+}
+}
+#endif
+
+#ifdef YOTTA_CORE_UTIL_VERSION_STRING
+// their functionality is implemented using the CriticalSectionLock class
+void utest_v1_enter_critical_section(void) {}
+void utest_v1_leave_critical_section(void) {}
+#endif