Add MCUboot bootloader and firmware update support

application/app/boards/custom_plank.conf

@@ -0,0 +1,36 @@
+# Copyright (c) 2021 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+#
+# Board-specific configuration for custom_plank (nrf52840).
+# Enables MCUboot integration and firmware update support via MCUmgr/SMP over UART.
+
+# ── MCUboot integration ────────────────────────────────────────────────────────
+# Tell Zephyr the application image is managed by MCUboot so it links the image
+# to slot0_partition and includes the image trailer expected by the bootloader.
+CONFIG_BOOTLOADER_MCUBOOT=y
+
+# ── Flash access ───────────────────────────────────────────────────────────────
+CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y
+CONFIG_FLASH_PAGE_LAYOUT=y
+CONFIG_STREAM_FLASH=y
+
+# ── Firmware image management ──────────────────────────────────────────────────
+# IMG_MANAGER tracks the update state (pending / confirmed / reverted).
+# IMG_ERASE_PROGRESSIVELY avoids erasing the entire slot before writing.
+CONFIG_IMG_MANAGER=y
+CONFIG_IMG_ERASE_PROGRESSIVELY=y
+
+# ── MCUmgr – management subsystem (SMP protocol) ──────────────────────────────
+CONFIG_MCUMGR=y
+CONFIG_NET_BUF=y
+CONFIG_ZCBOR=y
+CONFIG_CRC=y
+
+# SMP transport: expose the management interface over UART0.
+# Use `mcumgr` or `nrfutil device` on the host to upload images.
+CONFIG_MCUMGR_TRANSPORT_UART=y
+
+# Management command groups
+CONFIG_MCUMGR_GRP_IMG=y   # image upload / list / confirm / erase
+CONFIG_MCUMGR_GRP_OS=y    # reset, echo

application/app/sysbuild/mcuboot.conf

@@ -0,0 +1,35 @@
+# Copyright (c) 2021 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+#
+# MCUboot bootloader configuration used by Zephyr sysbuild.
+# Applied on top of MCUboot's own defaults when building with:
+#   west build --sysbuild -b custom_plank application/app
+#
+# Key references:
+#   https://docs.mcuboot.com/readme-zephyr.html
+#   https://docs.zephyrproject.org/latest/build/sysbuild/index.html
+
+# ── Swap strategy ──────────────────────────────────────────────────────────────
+# SWAP_USING_MOVE does not need a dedicated scratch sector; it moves sectors
+# one at a time using a small status area inside the image trailer.
+CONFIG_BOOT_SWAP_USING_MOVE=y
+
+# ── Flash sector budget ────────────────────────────────────────────────────────
+# Must be ≥ the number of flash sectors in the largest image slot.
+# slot0/slot1 = 448 KB / 4 KB per sector = 112 sectors → 256 is safe.
+CONFIG_BOOT_MAX_IMG_SECTORS=256
+
+# ── Image signing ──────────────────────────────────────────────────────────────
+# RSA-2048 is widely supported and straightforward to use with imgtool.
+# For production, replace the development key (root-rsa-2048.pem) with your own.
+CONFIG_BOOT_SIGNATURE_TYPE_RSA=y
+CONFIG_BOOT_SIGNATURE_TYPE_RSA_LEN=2048
+
+# ── Upgrade mode ──────────────────────────────────────────────────────────────
+# Allow permanent upgrades without requiring an explicit confirm().
+# Set to n (and confirm via MCUmgr) for stricter rollback safety.
+CONFIG_BOOT_UPGRADE_ONLY=n
+
+# ── Logging ────────────────────────────────────────────────────────────────────
+CONFIG_LOG=y
+CONFIG_MCUBOOT_LOG_LEVEL_INF=y

application/boards/vendor/custom_plank/custom_plank.dts

@@ -15,6 +15,7 @@
 		zephyr,console = &uart0;
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
+		zephyr,code-partition = &slot0_partition;
 	};
 
 	example_sensor: example-sensor {
@@ -58,3 +59,52 @@
 	pinctrl-1 = <&uart0_sleep>;
 	pinctrl-names = "default", "sleep";
 };
+
+/*
+ * Flash layout (1 MB total):
+ *
+ *   0x000000 +----------+ --\
+ *            | MCUboot  |   | 48 KB  (boot_partition)
+ *   0x00C000 +----------+ --+
+ *            | Slot 0   |   | 448 KB (slot0_partition – active image)
+ *   0x07C000 +----------+ --+
+ *            | Slot 1   |   | 448 KB (slot1_partition – update candidate)
+ *   0x0EC000 +----------+ --+
+ *            | Scratch  |   | 16 KB  (scratch_partition – swap workspace)
+ *   0x0F0000 +----------+ --+
+ *            | Storage  |   | 64 KB  (storage_partition – NVS/settings)
+ *   0x100000 +----------+ --/
+ */
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		boot_partition: partition@0 {
+			label = "mcuboot";
+			reg = <0x00000000 0x0000c000>;
+			read-only;
+		};
+
+		slot0_partition: partition@c000 {
+			label = "image-0";
+			reg = <0x0000c000 0x00070000>;
+		};
+
+		slot1_partition: partition@7c000 {
+			label = "image-1";
+			reg = <0x0007c000 0x00070000>;
+		};
+
+		scratch_partition: partition@ec000 {
+			label = "image-scratch";
+			reg = <0x000ec000 0x00004000>;
+		};
+
+		storage_partition: partition@f0000 {
+			label = "storage";
+			reg = <0x000f0000 0x00010000>;
+		};
+	};
+};

application/west.yml

@@ -14,3 +14,8 @@ manifest:
       remote: zephyrproject-rtos
       revision: main
       west-commands: scripts/west-commands.yml
+
+    - name: mcuboot
+      remote: zephyrproject-rtos
+      revision: main
+      path: bootloader/mcuboot

dfetch.yaml

@@ -34,3 +34,8 @@ manifest:
     revision: 57803da28e985e1cbc32a7ea993578f7267d0935
     repo-path: hal_stm32.git
     dst: modules/hal/stm32
+
+  - name: mcuboot # secure bootloader with firmware update support
+    repo-path: mcuboot.git
+    branch: main
+    dst: bootloader/mcuboot