.. _ble_mcuboot_recovery_retention_sample:

MCUboot: Recovery retention
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.. contents::
   :local:
   :depth: 2

This sample demonstrates how to reboot into `MCUboot`_'s recovery (firmware loader) mode using the retention boot mode subsystem.
See :ref:`ug_dfu` for details on DFU support in |BMshort|.

Requirements
************

The sample supports the following development kits:

.. include:: /includes/supported_boards_all_mcuboot_variants_s115.txt

.. include:: /includes/supported_boards_all_mcuboot_variants_s145.txt

Overview
********

After the application boots, it waits 3 seconds before setting the retention register for entering the firmware loader mode and then reboots the device.
The device then starts advertising the MCUmgr service allowing for a firmware update to be loaded.

Building and running
********************

This sample can be found under :file:`samples/boot/mcuboot_recovery_retention/` in the |BMshort| folder structure.

For details on how to create, configure, and program a sample, see :ref:`getting_started_with_the_samples`.

.. _ble_mcuboot_recovery_retention_sample_testing:

Testing
=======

1. Compile and program the application.
#. Connect the device to the computer to access UART 0.
   If you use a development kit, UART 0 is forwarded as a COM port (Windows) or ttyACM device (Linux) after you connect the development kit over USB.
#. Connect to the DK with a terminal emulator (for example, the `Serial Terminal app`_) to UART 0.
#. Reset the DK.
#. Observe that the device boots and reboots into firmware loader mode and then advertises with the default name ``nRF_BM_MCUmgr``.

   You can configure this name using the :kconfig:option:`CONFIG_APP_FIRMWARE_LOADER_BLE_DEVICE_NAME` Kconfig option of the ``firmware_loader`` image.
   For information on how to do this, see `Configuring Kconfig`_.
#. Connect to your device using the `nRF Connect Device Manager`_ mobile application.
#. Under the :guilabel:`image` tab, tap :guilabel:`Advanced`.
   Then, in the image control pane, tap :guilabel:`Read`.
   Observe that the details of the currently loaded application are displayed.