nRF Connect SDK Intermediate, Lesson 9, Exercise 4, problems with nrF53

[John-Eric Kamps]

Hi

SDK 3.4.1

Custom Board but with working USB-Interface from App

https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-4-dfu-over-usb/

If I configure it like described, I will get no USB-CDC device. The Serial port is present.

From my current understanding of mcuboot it is wrong to setup

STEP 1.1 - Configure serial recovery to use CDC_ACM, which by default uses the USB
CONFIG_MCUBOOT_SERIAL=y
CONFIG_BOOT_SERIAL_UART=y

It should be

STEP 1.1 - Configure serial recovery to use CDC_ACM, which by default uses the USB

CONFIG_MCUBOOT_SERIAL=y

CONFIG_BOOT_SERIAL_UART=n

CONFIG_BOOT_SERIAL_CDC_ACM=y

But with that I got an error:
2026-10-30T09:39:03.377Z C:/ncs/toolchains/4f5b6ad6dd/opt/zephyr-sdk/gnu/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/14.3.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: zephyr/subsys/usb/device_next/libsubsys__usb__device_next.a(usbd_cdc_acm.c.obj):C:/ncs/v3.4.1/zephyr/subsys/usb/device_next/class/usbd_cdc_acm.c:1386: multiple definition of `__device_dts_ord_190'; zephyr/libzephyr.a(cdc_acm.c.obj):C:/ncs/v3.4.1/zephyr/subsys/usb/device/class/cdc_acm.c:1229: first defined here

Is the usb-next driver not final in mcuboot for nrf53?

Best regards 

John

[John-Eric Kamps]

For documentation:

• Clean exercise 4
• Changes as diff:

  diff --git a/l9/l9_e4/sysbuild.conf b/l9/l9_e4/sysbuild.conf
  index 277d0a0..3b3365f 100644
  --- a/l9/l9_e4/sysbuild.conf
  +++ b/l9/l9_e4/sysbuild.conf
  @@ -1,4 +1,5 @@
   # Add MCUboot
   SB_CONFIG_BOOTLOADER_MCUBOOT=y
  -SB_CONFIG_MCUBOOT_USE_ALL_AVAILABLE_RAM=y
  +#Fix Build warning
  +SB_CONFIG_MCUBOOT_USE_ALL_AVAILABLE_RAM=n
   
  diff --git a/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay b/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay
  index 131d953..539601e 100644
  --- a/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay
  +++ b/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay
  @@ -7,4 +7,8 @@
   };
   
   /* STEP 2.1 - Configure CDC ACM */
  -
  +&zephyr_udc0 {
  +	cdc_acm_uart0: cdc_acm_uart0 {
  +		compatible = "zephyr,cdc-acm-uart";
  +	};
  +};
  diff --git a/l9/l9_e4/sysbuild/mcuboot/prj.conf b/l9/l9_e4/sysbuild/mcuboot/prj.conf
  index e736ae2..366f8f3 100644
  --- a/l9/l9_e4/sysbuild/mcuboot/prj.conf
  +++ b/l9/l9_e4/sysbuild/mcuboot/prj.conf
  @@ -20,7 +20,8 @@ CONFIG_NCS_APPLICATION_BOOT_BANNER_STRING="MCUboot"
   
   # Step 1.1 - Configure serial recovery to use CDC_ACM, which by default uses the USB
   CONFIG_MCUBOOT_SERIAL=y
  -CONFIG_BOOT_SERIAL_UART=y
  +CONFIG_BOOT_SERIAL_UART=n
  +CONFIG_BOOT_SERIAL_CDC_ACM=y
   
   # Disable console UART, since Serial Recovery uses UART
   CONFIG_UART_CONSOLE=n
  @@ -33,3 +34,8 @@ CONFIG_MCUBOOT_INDICATION_LED=y
   
   
   # STEP 1.2 - Enable USB subsystem 
  +CONFIG_USB_DEVICE_STACK_NEXT=y
  +CONFIG_MULTITHREADING=y
  +CONFIG_UART_USE_RUNTIME_CONFIGURE=y
  +CONFIG_UART_LINE_CTRL=y
  +#CONFIG_USBD_CDC_ACM_CLASS=y
  \ No newline at end of file
  

• Notes:
  • Deprecated USB_DEVICE_DRIVER and USB_DEVICE_STACK is enabled --> Looks wrong
  • MCUMGR_TRANSPORT_UART is disabled --> Looks wrong
  • Failure: region `FLASH' overflowed by 7908 bytes
• Will increase bootloader Flash size, because USB Next need more from my searching

Questions:

• Why it is not needed to change "zephyr,uart-mcumgr" from "uart0" to "&cdc_acm_uart0" in mcuboot overlay?
  • Like later for the application.