RW610 JLink DAP Failing on Zephyr

[jm-streametric]

Hello,

I am working on a custom PCB with an RW610 MCU and running Zephyr RTOS.  Before using Zephyr, I worked with FreeRTOS and the NXP HAL directly.

On that old firmware, I was able to use an external JLink debugger to reset/program the board even while running.  After switching to Zephyr, I can no longer flash while the board is running.  I get the message DAP failed to initialize.

On the custom board I do have a BOOT button which can force the board into ISP boot when powered off/on.  Using this, I can flash my Zephyr code.  However, I lose the ability to debug the code with GDB because when the board is flashed in ISP mode I can't reset it through the JLink.

Failed flash while running:

スポイラ

[2025-11-24T09:36:31.893] [Secure Provisioning] [error] No device id found.

[2025-11-24T09:36:32.392] [Secure Provisioning] [error] No device id found.

[2025-11-24T09:36:32.402] [proc] [info] Cmd: /opt/SEGGER/JLink_V872/JLinkGDBServerCLExe -listprobes USB

[2025-11-24T09:36:32.407] [proc] [info] Cmd: /usr/local/LinkServer_25.9.134/LinkServer probes --json

[2025-11-24T09:36:32.845] [proc] [info] Cmd: /usr/local/mcuxpressoide-24.12.148/ide/tools/bin/arm-none-eabi-gcc --version

[2025-11-24T09:36:32.850] [proc] [info] Cmd: /.../.mcuxpressotools/arm-gnu-toolchain-13.2.Rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc --version

[2025-11-24T09:36:32.856] [proc] [info] Cmd: /usr/local/mcuxpressoide/ide/tools/bin/arm-none-eabi-gcc --version

[2025-11-24T09:36:32.859] [proc] [info] Cmd: /.../.mcuxpressotools/arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc --version

[2025-11-24T09:36:32.866] [proc] [info] Cmd: cmake -DFORMAT=json -P verify-toolchain.cmake

[2025-11-24T09:36:33.815] [proc] [info] {"ZEPHYR_TOOLCHAIN_VARIANT" : "zephyr", "SDK_VERSION": "0.17.4", "ZEPHYR_SDK_INSTALL_DIR" : "/.../zephyr-sdk-0.17.4"}

[2025-11-24T09:36:33.821] [proc] [info] Cmd: /.../zephyr-sdk-0.17.4/arm-zephyr-eabi/bin/arm-zephyr-eabi-objcopy -I elf32-littlearm -O ihex /.../project/debug/zephyr/zephyr.elf zephyr.hex

[2025-11-24T09:36:33.842] [proc] [info] Cmd: /opt/SEGGER/JLink_V872/JLinkExe -if SWD -speed auto -commanderscript /.../project/script.jlink -device RW610 -SelectEmuBySN 53002466

[2025-11-24T09:36:34.285] [proc] [error] /opt/SEGGER/JLink_V872/JLinkExe exited with code 1

[2025-11-24T09:36:34.285] [proc] [error] SEGGER J-Link Commander V8.72 (Compiled Sep 24 2025 13:39:14)

DLL version V8.72, compiled Sep 24 2025 13:38:10

J-Link Command File read successfully.

Processing script file...

J-Link>ExitOnError 1

J-Link Commander will now exit on Error

J-Link>r

J-Link connection not established yet but required for command.

Connecting to J-Link via USB...O.K.

Firmware: J-Link V13 compiled Sep 17 2025 12:01:59

Hardware version: V13.00

J-Link uptime (since boot): 0d 00h 08m 51s

S/N: 53002466

License(s): GDB

USB speed mode: High speed (480 MBit/s)

VTref=3.322V

Target connection not established yet but required for command.

Device "RW610" selected.

Connecting to target via SWD

InitTarget() start

SWD selected. Executing JTAG -> SWD switching sequence.

Error: Failed to initialize DAP.

InitTarget() end - Took 133ms

Connect failed. Resetting via Reset pin and trying again.

InitTarget() start

SWD selected. Executing JTAG -> SWD switching sequence.

Error: Failed to initialize DAP.

InitTarget() end - Took 133ms

Error occurred: Could not connect to the target device.

For troubleshooting steps visit: https://kb.segger.com/J-Link_Troubleshooting

Script processing completed.

Successful flash when I use ISP boot:

スポイラ

[2025-11-24T09:34:03.519] [Secure Provisioning] [error] No device id found.
[2025-11-24T09:34:04.494] [Secure Provisioning] [error] No device id found.
[2025-11-24T09:34:04.503] [proc] [info] Cmd: /opt/SEGGER/JLink_V872/JLinkGDBServerCLExe -listprobes USB
[2025-11-24T09:34:04.507] [proc] [info] Cmd: /usr/local/LinkServer_25.9.134/LinkServer probes --json
[2025-11-24T09:34:04.948] [proc] [info] Cmd: /usr/local/mcuxpressoide-24.12.148/ide/tools/bin/arm-none-eabi-gcc --version
[2025-11-24T09:34:04.953] [proc] [info] Cmd: /usr/local/mcuxpressoide/ide/tools/bin/arm-none-eabi-gcc --version
[2025-11-24T09:34:04.959] [proc] [info] Cmd: /.../.mcuxpressotools/arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc --version
[2025-11-24T09:34:04.963] [proc] [info] Cmd: /.../.mcuxpressotools/arm-gnu-toolchain-13.2.Rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc --version
[2025-11-24T09:34:04.972] [proc] [info] Cmd: cmake -DFORMAT=json -P verify-toolchain.cmake
[2025-11-24T09:34:06.130] [proc] [info] {"ZEPHYR_TOOLCHAIN_VARIANT" : "zephyr", "SDK_VERSION": "0.17.4", "ZEPHYR_SDK_INSTALL_DIR" : "/.../zephyr-sdk-0.17.4"}

[2025-11-24T09:34:06.136] [proc] [info] Cmd: /.../zephyr-sdk-0.17.4/arm-zephyr-eabi/bin/arm-zephyr-eabi-objcopy -I elf32-littlearm -O ihex /.../project/debug/zephyr/zephyr.elf zephyr.hex
[2025-11-24T09:34:06.157] [proc] [info] Cmd: /opt/SEGGER/JLink_V872/JLinkExe -if SWD -speed auto -commanderscript /.../project/script.jlink -device RW610 -SelectEmuBySN 53002466
[2025-11-24T09:34:20.074] [SEGGER] [info] SEGGER flash operation completed successfully:
SEGGER J-Link Commander V8.72 (Compiled Sep 24 2025 13:39:14)
DLL version V8.72, compiled Sep 24 2025 13:38:10

J-Link Command File read successfully.
Processing script file...
J-Link>ExitOnError 1
J-Link Commander will now exit on Error
J-Link>r
J-Link connection not established yet but required for command.
Connecting to J-Link via USB...O.K.
Firmware: J-Link V13 compiled Sep 17 2025 12:01:59
Hardware version: V13.00
J-Link uptime (since boot): 0d 00h 06m 24s
S/N: 53002466
License(s): GDB
USB speed mode: High speed (480 MBit/s)
VTref=3.325V
Target connection not established yet but required for command.
Device "RW610" selected.

Connecting to target via SWD
InitTarget() start
SWD selected. Executing JTAG -> SWD switching sequence.
DAP initialized successfully.
DMAP_REG_ID: DM-AP IDCODE detected: 0x002A0000
DHCSR: 0xFFFFFFFF
ROM entered ISP command handling loop. Re-enable the debug access.
InitTarget() end - Took 14.0ms
Found SW-DP with ID 0x6BA02477
DPIDR: 0x6BA02477
CoreSight SoC-400 or earlier
Scanning AP map to find all available APs
AP[1]: Stopped AP scan as end of AP map has been reached
AP[0]: AHB-AP (IDR: 0x84770001, ADDR: 0x00000000)
Iterating through AP map to find AHB-AP to use
AP[0]: Core found
AP[0]: AHB-AP ROM base: 0xE00FF000
CPUID register: 0x410FD214. Implementer code: 0x41 (ARM)
Feature set: Mainline
Cache: No cache
Found Cortex-M33 r0p4, Little endian.
FPUnit: 8 code (BP) slots and 0 literal slots
Security extension: implemented
Secure debug: enabled
CoreSight components:
ROMTbl[0] @ E00FF000
[0][0]: E000E000 CID B105900D PID 000BBD21 DEVARCH 47702A04 DEVTYPE 00 Cortex-M33
[0][1]: E0001000 CID B105900D PID 000BBD21 DEVARCH 47701A02 DEVTYPE 00 DWT
[0][2]: E0002000 CID B105900D PID 000BBD21 DEVARCH 47701A03 DEVTYPE 00 FPB
[0][3]: E0000000 CID B105900D PID 000BBD21 DEVARCH 47701A01 DEVTYPE 43 ITM
[0][5]: E0041000 CID B105900D PID 002BBD21 DEVARCH 47724A13 DEVTYPE 13 ETM
[0][6]: E0042000 CID B105900D PID 000BBD21 DEVARCH 47701A14 DEVTYPE 14 CSS600-CTI
Memory zones:
Zone: "Default" Description: Default access mode
Cortex-M33 identified.
Reset delay: 0 ms
ResetTarget() start
Reset via SYSRESETREQ and reset pin + halt after bootloader
ROM entered ISP command handling loop. Re-enable the debug access.
MSPLIM cleared
ResetTarget() end - Took 128ms
Device specific reset executed.
J-Link>h
PC = 1302B460, CycleCnt = 00000000
R0 = 00000000, R1 = 5AC33CA5, R2 = 00000001, R3 = 5AC33CA5
R4 = 3012F5FC, R5 = 50002E24, R6 = 55AACC33, R7 = 33CCAA55
R8 = 5AA55AA5, R9 = FCF0030F, R10= C33CA55A, R11= 55AACC33
R12= 3012F5FC
SP(R13)= 30125A38, MSP= 30125A38, PSP= 00000000, R14(LR) = 1302B421
XPSR = 01000000: APSR = nzcvq, EPSR = 01000000, IPSR = 000 (NoException)
CFBP = 00000001, CONTROL = 00, FAULTMASK = 00, BASEPRI = 00, PRIMASK = 01
MSPLIM = 00000000
PSPLIM = 00000000

Security extension regs:
MSP_S = 30125A38, MSP_NS = 00000000
MSPLIM_S = 00000000, MSPLIM_NS = 00000000
PSP_S = 00000000, PSP_NS = FFFFFFFC
PSPLIM_S = 00000000, PSPLIM_NS = 00000000
CONTROL_S = 00, FAULTMASK_S = 00, BASEPRI_S = 00, PRIMASK_S = 01
CONTROL_NS = 00, FAULTMASK_NS = 00, BASEPRI_NS = 00, PRIMASK_NS = 00

FPS0 = 00000000, FPS1 = 00000000, FPS2 = 00000000, FPS3 = 00000000
FPS4 = 00000000, FPS5 = 00000000, FPS6 = 00000000, FPS7 = 00000000
FPS8 = 00000000, FPS9 = 00000000, FPS10= 00000000, FPS11= 00000000
FPS12= 00000000, FPS13= 00000000, FPS14= 00000000, FPS15= 00000000
FPS16= 00000000, FPS17= 00000000, FPS18= 00000000, FPS19= 00000000
FPS20= 00000000, FPS21= 00000000, FPS22= 00000000, FPS23= 00000000
FPS24= 00000000, FPS25= 00000000, FPS26= 00000000, FPS27= 00000000
FPS28= 00000000, FPS29= 00000000, FPS30= 00000000, FPS31= 00000000
FPSCR= 00000000
J-Link>loadfile /.../project/debug/zephyr/zephyr.hex
'loadfile': Performing implicit reset & halt of MCU.
ResetTarget() start
Reset via SYSRESETREQ and reset pin + halt after bootloader
ROM entered ISP command handling loop. Re-enable the debug access.
MSPLIM cleared
ResetTarget() end - Took 117ms
Device specific reset executed.
Downloading file [/.../project/debug/zephyr/zephyr.hex]...
J-Link: Flash download: Bank 1 @ 0x18000000: 1 range affected (786432 bytes)
J-Link: Flash download: Total: 13.012s (Prepare: 0.333s, Compare: 2.685s, Erase: 2.979s, Program: 5.531s, Verify: 1.307s, Restore: 0.174s)
J-Link: Flash download: Program speed: 139 KB/s
O.K.
J-Link>qc

Script processing completed.

Since the flashing worked when using FreeRTOS I suspect I have something in the devicetree or KConfig configured incorrectly.  Is there anything I should look for there?
I am using the MCUXpresso VSCode extension on Linux, flashing Zephyr 4.3.0.

Thank you!

[DanielRuvalcaba]

Hi,

Are you able to use the J-Link Commander CLI to communicate with the core? (not in VS code)

What example did you use?

Regards,
Daniel.