[nrf noup] boot/zephyr/boards: defaults nrf54lm20dongle

Define defaults for nRF54LM20 Dongle so this target can have the
bootloader enabled by default for all applications without having to
provide extra overlays for the MCUBoot.

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>
(cherry picked from commit d36845e)

Author: Damian-Nordic

boot/zephyr/boards/nrf54lm20dongle_nrf54lm20b_cpuapp.conf

@@ -0,0 +1,39 @@
+#
+# Copyright (c) 2026 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_BOOT_FIRMWARE_LOADER_ENTRANCE_GPIO=y
+CONFIG_BOOT_FIRMWARE_LOADER_NO_APPLICATION=y
+CONFIG_GPIO=y
+CONFIG_CRACEN_IKG=n
+CONFIG_NRF_RRAM_WRITE_BUFFER_SIZE=32
+CONFIG_NCS_MCUBOOT_DISABLE_SELF_RWX=y
+
+# Disable run-time CRACEN provisioning of TRNG data.
+# KMU slots 248, 249 shall be pre-provisioned while programming with secret TRNG values instead.
+CONFIG_CRACEN_PROVISION_PROT_RAM_INV_SLOTS_ON_INIT=n
+
+# Reduce memory consumption
+CONFIG_LOG=n
+CONFIG_BOOT_BANNER=n
+CONFIG_NCS_BOOT_BANNER=n
+CONFIG_NCS_APPLICATION_BOOT_BANNER_STRING=""
+CONFIG_CLOCK_CONTROL=n
+CONFIG_NRF_GRTC_START_SYSCOUNTER=n
+CONFIG_SPI_NOR=n
+CONFIG_SERIAL=n
+CONFIG_CONSOLE=n
+CONFIG_UART_CONSOLE=n
+CONFIG_PRINTK=n
+CONFIG_USE_SEGGER_RTT=n
+CONFIG_SYS_CLOCK_EXISTS=n
+CONFIG_NRF_GRTC_TIMER=n
+
+# Activate Link Time Optimization (LTO)
+CONFIG_LTO=y
+CONFIG_ISR_TABLES_LOCAL_DECLARATION=y
+
+# Improve debugging experience by disabling reset on fatal error
+CONFIG_RESET_ON_FATAL_ERROR=n

boot/zephyr/boards/nrf54lm20dongle_nrf54lm20b_cpuapp.overlay

@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
+/ {
+	chosen {
+		zephyr,code-partition = &boot_partition;
+	};
+};
+
 /* This is nRF54lm20dongle_nrf54lm20b_cpuapp peculiar partitioning for MCUboot and firmware loader
  * slot0_partition spans RRAM with can be update by the firmware loader and booted by MCUboot.
  * beginning of the slot0_partition must match with the beginning of the slot0_partition of the user

boot/zephyr/socs/nrf54lm20b_cpuapp.conf

@@ -9,5 +9,3 @@ CONFIG_SPI_NOR=n
 
 # TODO: below are not yet supported and need fixing
 CONFIG_FPROTECT=n
-
-CONFIG_BOOT_WATCHDOG_FEED=n