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

[AHaug]

Hi John,

That is correct, usb next is not an option for the nrf5340. It will alsways select the legacy USB device stack. The kconfig to enable USB next selects only Next for nRF54 series devices

config BOOT_SERIAL_CDC_ACM
	bool "CDC ACM"
	select USB_DEVICE_STACK if !(SOC_NRF54LM20A || SOC_NRF54LM20B)
	select USB_DEVICE_STACK_NEXT if (SOC_NRF54LM20A || SOC_NRF54LM20B)

We'll look into the exercise and double check if and what is wrong/not working for the non nRF54LM20 devices.

Kind regards,
Andreas

[AHaug]

Hi again,

The author agrees that a fix is required. They will make an update to the course to either highlight the different requirement for the SoCs and/or patch the issue. Resolution is TBD and depends on what is supported in the SDK tag.

Reassigning the case to them and leaving it as open.

Thank you for reporting this,

Kind regards,
Andreas

[John-Eric Kamps]

Attached are my working example for nrf53 on SDK 3.4.1.

diff --git a/l9/l9_e4/prj.conf b/l9/l9_e4/prj.conf
index 9200873..2763b9c 100644
--- a/l9/l9_e4/prj.conf
+++ b/l9/l9_e4/prj.conf
@@ -1,33 +1,19 @@
 CONFIG_GPIO=y
 
 # Enable MCUboot
-CONFIG_BOOTLOADER_MCUBOOT=y
-
 # Enable mcumgr DFU in application
-CONFIG_MCUMGR=y
-
 # Enable MCUMGR management for both OS and Images
-CONFIG_MCUMGR_GRP_OS=y
-CONFIG_MCUMGR_GRP_IMG=y
 
 # Configure MCUMGR transport to UART
-CONFIG_MCUMGR_TRANSPORT_UART=y
 
 # Dependencies
 # Configure dependencies for CONFIG_MCUMGR  
-CONFIG_NET_BUF=y
-CONFIG_ZCBOR=y
-CONFIG_CRC=y
 
 # Configure dependencies for CONFIG_MCUMGR_GRP_IMG  
-CONFIG_FLASH=y
-CONFIG_IMG_MANAGER=y
 
 # Configure dependencies for CONFIG_IMG_MANAGER  
-CONFIG_STREAM_FLASH=y
-CONFIG_FLASH_MAP=y
 
 # Configure dependencies for CONFIG_MCUMGR_TRANSPORT_UART 
-CONFIG_BASE64=y
+
 
 # STEP 5.3 - Enable USB subsystem
diff --git a/l9/l9_e4/sysbuild.conf b/l9/l9_e4/sysbuild.conf
index 277d0a0..e40de37 100644
--- a/l9/l9_e4/sysbuild.conf
+++ b/l9/l9_e4/sysbuild.conf
@@ -1,4 +1,3 @@
 # Add MCUboot
 SB_CONFIG_BOOTLOADER_MCUBOOT=y
-SB_CONFIG_MCUBOOT_USE_ALL_AVAILABLE_RAM=y
 
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..7ca9ce0 100644
--- a/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay
+++ b/l9/l9_e4/sysbuild/mcuboot/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -3,8 +3,13 @@
 / {
 	chosen {
 		zephyr,code-partition = &boot_partition;
+		zephyr,uart-mcumgr = &cdc_acm_uart0;
 	};
 };
 
 /* 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..2c53899 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 +34,7 @@ CONFIG_MCUBOOT_INDICATION_LED=y
 
 
 # STEP 1.2 - Enable USB subsystem 
+CONFIG_USB_DEVICE_STACK_NEXT=n
+CONFIG_MULTITHREADING=y
+CONFIG_UART_USE_RUNTIME_CONFIGURE=y
+CONFIG_UART_LINE_CTRL=y

From my point it could be closed.