Simultaneous multi-image DFU with usb is failed(Serial recovery, external flash)

Question

I try to simultaneous update (app + networkcore) with usb and external flash on my custombord And serial recovery, not DFU from app. 
 this is mcuboot config. I have set the configuration of simultaenous multi-core updates. 
 # Enable Serial Recovery over UART
CONFIG_MCUBOOT_SERIAL=y
CONFIG_BOOT_SERIAL_UART=y
# Disable UART, since Serial Recovery uses it
CONFIG_UART_CONSOLE=n
# Configure boolader to use only one slot. 
CONFIG_SINGLE_APPLICATION_SLOT=n
# Turn on a LED so we can see when Serial Recovery mode is active
CONFIG_MCUBOOT_INDICATION_LED=y
# Configure serial recovery to use CDC_ACM, which by default uses the USB
CONFIG_BOOT_SERIAL_CDC_ACM=y
# Increase flash space for MCUboot child image, to fit USB drivers
CONFIG_PM_PARTITION_SIZE_MCUBOOT=0x16000

# Enable Retention 
CONFIG_RETENTION=y
CONFIG_RETAINED_MEM=y
CONFIG_RETAINED_MEM_ZEPHYR_RAM=y
CONFIG_RETENTION_BOOT_MODE=y
# Enable Reboot
CONFIG_REBOOT=y

# Set Boot Type
CONFIG_BOOT_SERIAL_BOOT_MODE=y
CONFIG_BOOT_SERIAL_NO_APPLICATION=y
CONFIG_BOOT_SERIAL_ENTRANCE_GPIO=n

CONFIG_USB_DEVICE_PID=0x0001

CONFIG_BOOT_MAX_LINE_INPUT_LEN=1024

CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256=y

# Enable logging for MCUboot
CONFIG_LOG=y
CONFIG_MCUBOOT_LOG_LEVEL_WRN=y

# Reduce flash useage
CONFIG_CBPRINTF_NANO=y

# Enable QSPI driver for external flash
CONFIG_NORDIC_QSPI_NOR=y
# Increase number of sectors
CONFIG_BOOT_MAX_IMG_SECTORS=256

# Enable simultaenous multi-core updates
CONFIG_NRF53_MULTI_IMAGE_UPDATE=y
CONFIG_UPDATEABLE_IMAGE_NUMBER=2
CONFIG_BOOT_UPGRADE_ONLY=y
CONFIG_PCD_APP=y

# Dependencies for CONFIG_NRF53_MULTI_IMAGE_UPDATE
CONFIG_FLASH=y
CONFIG_FLASH_SIMULATOR=y
CONFIG_FLASH_SIMULATOR_DOUBLE_WRITES=y
CONFIG_FLASH_SIMULATOR_STATS=n And this is prj.conf # Disable fatal error reset
CONFIG_RESET_ON_FATAL_ERROR=n

# Enable RTT
CONFIG_USE_SEGGER_RTT=y

# Enable console
CONFIG_CONSOLE=y
CONFIG_LOG=y

# Enable RTOS Events
CONFIG_EVENTS=y

# Enable USB Driver
CONFIG_SERIAL=y
CONFIG_USB_DEVICE_STACK=y
CONFIG_USB_DEVICE_PID=0x0001
CONFIG_LOG_BACKEND_RTT=n

# Enable MCUboot
CONFIG_BOOTLOADER_MCUBOOT=y

# Enable Retention
CONFIG_RETENTION=y
CONFIG_RETAINED_MEM=y
CONFIG_RETAINED_MEM_ZEPHYR_RAM=y
CONFIG_RETENTION_BOOT_MODE=y

# Enable Reboot
CONFIG_REBOOT=y

# Enable cmsis-dsp
CONFIG_CMSIS_DSP=y
# Build with NewLib
CONFIG_NEWLIB_LIBC=y
# Enable FPU
CONFIG_FPU=y 
 I have also set up the configuration to use external Flash. 
/ {
 chosen {
 nordic,pm-ext-flash = &mx25u128;
	};
}; 
 this is partation

I try to dfu with mcumgr command line tool, and I use dfu_application.zip this is the image list before upload. Images:
 image=0 slot=0
 version: 0.0.0
 bootable: false
 flags:
 hash: 63c737a287db489da724bbbbeb64be46615c55a192bf014910ba3773141ffd60
 image=1 slot=0
 version: 0.0.0
 bootable: false
 flags:
 hash: Unavailable
Split status: N/A (0) this is the image list after upload dfu_application.zip. Images:
 image=1 slot=0
 version: 0.0.0
 bootable: false
 flags:
 hash: Unavailable
Split status: N/A (0) It is complete to upload dfu_application.zip but after reset, the nw app doesn't start. The bootloader is running, but the app doesn't seem to be running. I attach this file. 
 4454.dfu_application.zip Why can't I update simultaneously even though I have the configuration set? In the first place, is it not possible to perform simultaneous updates using an external flash with serial recovery? 
 When updating simultaneously, I entered "mcumgr -c testDK image upload hoge\dfu_application.zip", but is this incorrect? 
 Please let me know if you know anything. 
 best regards.