[nrf noup] boot/zephyr: add nrf54l15dk ext flash configs

boot/zephyr/Kconfig

@@ -202,7 +202,7 @@ config BOOT_SIGNATURE_TYPE_PURE_ALLOW
 
 choice BOOT_SIGNATURE_TYPE
 	prompt "Signature type"
-	default BOOT_SIGNATURE_TYPE_ED25519 if BOARD_NRF54L15PDK_NRF54L15_CPUAPP
+	default BOOT_SIGNATURE_TYPE_ED25519 if SOC_NRF54L15_CPUAPP
 	default BOOT_SIGNATURE_TYPE_RSA
 
 config BOOT_SIGNATURE_TYPE_NONE

boot/zephyr/boards/nrf54l15dk_nrf54l15_cpuapp_ext_flash.conf

@@ -0,0 +1,15 @@
+CONFIG_MULTITHREADING=y
+CONFIG_SPI=y
+CONFIG_SPI_NOR=y
+CONFIG_FLASH=y
+CONFIG_PM_PARTITION_SIZE_MCUBOOT=0x14000
+CONFIG_MAIN_STACK_SIZE=20480
+CONFIG_BOOT_MAX_IMG_SECTORS=512
+CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096
+# Ensure that the qspi driver is disabled by default
+CONFIG_NORDIC_QSPI_NOR=n
+
+# TODO: below are not yet supported and need fixing
+CONFIG_FPROTECT=n
+
+CONFIG_BOOT_WATCHDOG_FEED=n

boot/zephyr/boards/nrf54l15dk_nrf54l15_cpuapp_ext_flash.overlay

@@ -0,0 +1,47 @@
+/ {
+	chosen {
+		nordic,pm-ext-flash = &mx25r64;
+		zephyr,code-partition = &boot_partition;
+	};
+};
+
+/delete-node/ &boot_partition;
+/delete-node/ &slot0_partition;
+/delete-node/ &slot1_partition;
+
+/delete-node/ &slot0_ns_partition;
+/delete-node/ &slot1_ns_partition;
+
+/delete-node/ &storage_partition;
+
+&cpuapp_rram {
+	reg = < 0x0 DT_SIZE_K(1524) >;
+	partitions {
+		boot_partition: partition@0 {
+			label = "mcuboot";
+			reg = <0x000000000 0x00014000>;
+		};
+		slot0_partition: partition@14000 {
+			label = "image-0";
+			reg = <0x000014000 0x0015A000>;
+		};
+		storage_partition: partition@16E000 {
+			label = "storage";
+			reg = < 0x16E000 0x9000 >;
+		};
+	};
+};
+
+&mx25r64 {
+	status = "okay";
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		slot1_partition: partition@0 {
+			label = "image-1";
+			reg = <0x000000000 0x0015A000>;
+		};
+	};
+};