blhost Error

[priyanshua1]

Hello,

I am trying to play with NXP KW45B41Z-EVK board. However, going forward with their user guide page (Getting Started with the KW45B41Z Evaluation Kit | NXP Semiconductors), i am facing issue to flash the J-Link/CMSIS-DAP firmware into the board.

Error:

J-Link firmware for MCU-Link programming script v3.0 June 2025.

NOTE: J-Link firmware supports MCU-Link Pro and MCU-Link on-board systems
that use an LPC55S16 or an LPC55S69 in LQFP100 or BGA98 package.
Although the firmware can be programmed in to MCU-Link and MCU-Link on-board
systems that use LPC55S69 LQFP64 package, the firmware will not run.

Place the board in ISP USB mode using the appropriate jumper on your MCU-Link.
Refer to the board documentation for more information.
Connect board via USB then press Space.
Error: Cannot find blhost. Check BlhostHome path!

[priyanshua1]

Hello Luis,

I’m currently facing an issue installing the drivers mentioned in Section 2.4 of the documentation Getting Started with the KW45B41Z Evaluation Kit | NXP Semiconductors. As per your recommendation, I referred to the MCUXpresso SDK Documentation regarding updating the debugger firmware. However, Section 2.4 of the Getting Started page indicates same.

My goal is to set up the KW45B41Z-EVK board with MCUXpresso IDE and begin experimenting with various use cases.
I’ve attached an image of the connected board and will also share the error message below: 
Error Message:

J-Link firmware for MCU-Link programming script v3.0 June 2025. NOTE: J-Link firmware supports MCU-Link Pro and MCU-Link on-board systems that use an LPC55S16 or an LPC55S69 in LQFP100 or BGA98 package. Although the firmware can be programmed into MCU-Link and MCU-Link on-board systems that use LPC55S69 LQFP64 package, the firmware will not run.

Place the board in ISP USB mode using the appropriate jumper on your MCU-Link.

Refer to the board documentation for more information. Connect board via USB then press Space.

Error: Cannot find blhost. Check BlhostHome path! I’ve also installed blhost from the official MCU Bootloader page on NXP Semiconductors.

Please guide me on resolving this issue.

[luis_maravilla]

The message indicates the missing of the blhost [cannot find blhost] This tool is implemented inside the SPSDK, as described in the image from section 2.5 applications section. [Getting started]. Could you help us confirm that the installation of the SPSDK tool from section 2.5 were install without problems? If not I would recommend trying installing the SPSDK tool for the blhost app and retry the section 2.4 Installing drivers as your configuration of the board its correct for this step.

When installing MCUXpresso IDE in step 2.1, recent versions of IDE have the blhost by default; could you help us confirm what MCUXpresso IDE version and SDK version are you intended to use? I would recommend using the lates version [25.06].

[priyanshua1]

Hello,

Yes, section 2.5 (SPSDK) has been installed correctly.
I'm currently using MCUXpresso v25.6.

However, I'm still encountering the same issue.
Are there any additional configurations I need to perform?

If possible, could you please share a step-by-step guide from scratch to help resolve this?

Thanks!

[luis_maravilla · Accepted solution]

Hello,

Thank you for the information.

I'm going to Refer to Section 2.4 Install Drivers from the Getting Started with the KW45B41Z Evaluation Kit | NXP Semiconductors

Instruction 1-3 Redirects to you to install the package for your host OS [I added the OS options below]

MCU-Link installer for MacOS (USB HID) (v2.263)

MCU-Link installer for Windows 10/11 (USB HID) (v2.263)

MCU-Link installer for Linux (v2.263)

Could you confirm when downloading the Package for your host OS, in the MCU-LINK_installer_Vx_xxx directory, what version is shown?

MCU-Link_installer_3.160 or lower version?

Could you verify if the blhost.exe file is in MCU-LINK_installer_Vx_xxx\bin folder please?

Also, if you have downloaded another version different from MCU-Link installer, I would recommend changing to v2.263 as the link for your OS applies.

If you don’t have the blhost.exe file you can Download the blhost application from this link. Bootloader Host Application (blhost)

Instruction 4 is the configuration by shorting jumper JP20 [Confirmed jumper configuration in previously shared photo]

Instruction 5 says connect the J14 connector on the board and with jumper JP20 MCU-Link gets powered up in (USB) ISP mode.

Instruction 6 Indicates first follow the instructions provided in the "Firmware Installation Guide" section of the "Readme.txt" file.  found in the MCU-LINK_installer_Vx_xxx_directory

Then To install J-Link firmware, open a command prompt in the MCU-LINK_installer_Vx_xxx folder direction and call the program script:

    <Install Dir>\scripts\program_JLINK

You should see a message in the command prompt "Programming Firmware_J-Link-MCU-Link_v.s19" and "Programmed succesfully

Please Let me know if this information helps you and your findings about this.

Best Regards

Luis

[priyanshua1]

Hi Luis,

Thank you very much for your continued support.

I've successfully tested the board configurations and the Hello World demo. As the next step, I’d like to pair the KW45B41Z-EVK board with a mobile device.

Could you please let me know if there’s an existing workflow or documentation available for this process? If not, I’d appreciate guidance on how to define the pairing procedure from scratch.

Additionally, I’m interested in transmitting custom data packets over BLE once the connection is established. Could you advise on the recommended approach or APIs for implementing this?

[luis_maravilla]

Hello, Glad to hear that!

To pair KW45B41Z-EVK board with a mobile device, please download the NXP IoT Toolbox available for Android and IOS.

The instructions and guidance about the Wireless examples are described in Bluetooth Low Energy Demo Applications User’s Guide and in each example README file.

If you want to transmit custom data over BLE, I would reccommend testing the base example first and then taking the code as a base for modifying to your project requirements.

For all modifications implemented the Bluetooth Low Energy Application Developer’s Guide would guide you as this document explains how to integrate the NXP Bluetooth Low Energy Host Stack in an application and provides detailed explanation of the most commonly used APIs and code examples.

Thank you for your interest in NXP Semiconductor products!

Best Regards

Luis

[luis_maravilla]

Hello,

Could you help us confirm if you can install the drivers described in section 2.4 [ Getting Started] without problems please?

If you need to reprogram the debugger firmware, I recommend the following page Updating debugger firmware — MCUXpresso SDK Documentation

Also, could you share with us a photo of your setup for the KW45B41Z-EVK board, I want to confirm the jumper configuration.

Could you help us confirm if you are following the Getting started using MCUXpresso IDE tool or Visual Studio code?

Best Regards

Luis