[nrf fromlist] boards: nrf54h20dk: Limit app core FLASH_LOAD_SIZE

Upstream PR #: 91413

CONFIG_USE_DT_CODE_PARTITION had to be disabled to add MCUboot support.
As a result, CONFIG_FLASH_LOAD_SIZE was left at zero, which means that
the linker would claim all available MRAM for the app core.

For now, we can't allow that, because the default nRF54H20 DK memory map
divides MRAM between multiple cores in order to support various samples.

Signed-off-by: Grzegorz Swiderski <[email protected]>
(cherry picked from commit 66b0151a5621267a40290c43f1079fe691cc4837)

Author: 57300

boards/nordic/nrf54h20dk/Kconfig.defconfig

@@ -12,9 +12,16 @@ config MAX_THREAD_BYTES
 config ROM_START_OFFSET
 	default 0x800 if BOOTLOADER_MCUBOOT
 
+# Application core firmware must start at this offset when not using MCUboot.
+# However, the default 'zephyr,code-partition' in DT is set for MCUboot.
 config FLASH_LOAD_OFFSET
 	default 0x2c000 if !USE_DT_CODE_PARTITION
 
+# This is meant to span 'cpuapp_boot_partition' and 'cpuapp_slot0_partition'
+# in the default memory map.
+config FLASH_LOAD_SIZE
+	default 0x64000 if !USE_DT_CODE_PARTITION
+
 endif # BOARD_NRF54H20DK_NRF54H20_CPUAPP
 
 if BOARD_NRF54H20DK_NRF54H20_CPURAD

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpuapp_0_9_0.yaml

@@ -10,7 +10,7 @@ toolchain:
   - zephyr
 sysbuild: true
 ram: 256
-flash: 296
+flash: 400
 supported:
   - adc
   - can