LTE Modem over J-Link

This article describes how to flash the LTE modem firmware in CHESTER using SEGGER J-Link.

Requirements

You will need the following hardware and software tools:

• One of these operating systems:

  • Ubuntu version 24.04
  • macOS version 15 (with Homebrew installed)
  • Windows version 11

• Python 3 distribution installed on your system:

  Ubuntu

  Run this command in the Terminal app:

  sudo apt install python3

  macOS

  Run this command in the Terminal app:

  brew install python3

  Windows

  Download the latest stable installer from this link.

  caution

  Ensure the Windows installer can modify the PATH variable so the Python executable is available from any location.

• CHESTER device (you will need to open the enclosure top cover with six screws)

• USB debugger/programmer SEGGER J-Link (including a 10-pin SWD adapter + flat cable)

  tip

  HARDWARIO provides J-Link + all the required accessories on demand.

• Micro-USB cable with appropriate plug type to your computer

  danger

  Some Micro-USB cables provide only power and no data signals. If the connection between J-Link, and your system does not work, check the cable type in the first place.

• Python application bundle HARDWARIO Command Line Tools

Installation

You can install HARDWARIO Command Line Tools with these steps:

1. On Windows only - Install the SEGGER J-Link drivers:

   • Download 64-bit Intel/AMD installer
   • Download 32-bit Intel/AMD installer
   • Download 64-bit ARM installer

2. Open the Terminal (Ubuntu or macOS) or Command Prompt (Windows) application.

3. Initialize the Python virtual environment:

   python3 -m venv hardwario-venv

4. Activate the Python virtual environment:

   Ubuntu

   source hardwario-venv/bin/activate

   macOS

   source hardwario-venv/bin/activate

   Windows

   hardwario-venv\Scripts\activate.bat

   caution

   When you close the Terminal or Command Prompt, you must reactivate the Python virtual environment. Simply repeat the appropriate command for the given platform above.

5. Install HARDWARIO Command Line Tools:

   pip install hardwario

6. You can verify the installation with the following command:

   hardwario --version

   It should provide output similar to this:

   hardwario.chester v1.19.0
   hardwario.cloud v1.4.1
   hardwario.common v1.7.1
   hardwario.hardwario v1.2.0

Flashing Procedure

Follow these steps to flash the LTE modem firmware in the CHESTER device:

1. Open the CHESTER enclosure (6 screws from the bottom side).

2. Connect the 10-pin flat cable to the connector labeled APP (or BLE on hardware revision R3.2 and earlier).

   caution

   One of the wires on the flat cable between SEGGER J-Link and CHESTER has red color. This red color denotes signal number 1. This red-colored signal has to be oriented toward the black dot located next to the SWD connector on the CHESTER mainboard. The same rule with the cable applies at the side of SEGGER J-Link.

3. Connect the other side of the 10-pin flat cable to the SEGGER J-Link adapter board (and plug the adapter board into the SEGGER J-Link device).

4. Connect the Micro-USB cable to your computer and SEGGER J-Link.

5. Open the Terminal (Ubuntu or macOS) or Command Prompt (Windows) application.

6. Activate the Python virtual environment where you have installed the HARDWARIO Command Line Tools (see the previous chapter).

7. Run this command to erase the application firmware:

   hardwario chester app erase

   tip

   The application firmware erase is required in order to prevent the reset signal collision between SEGGER J-Link and the application firmware.

8. Connect the 10-pin flat cable to the connector labeled LTE.

   caution

   One of the wires on the flat cable between SEGGER J-Link and CHESTER has red color. This red color denotes signal number 1. This red-colored signal has to be oriented toward the black dot located next to the SWD connector on the CHESTER mainboard. The same rule with the cable applies at the side of SEGGER J-Link.

9. Download the LTE modem firmware package v1.7.0.

   info

   If you are looking for the LTE modem firmware compatible with the LTE v1 communication stack for the HARDWARIO Cloud v1 service, you need to download and flash v1.3.0.

10. Run this command to flash the LTE modem firmware:

    hardwario chester lte flash hio-chester-lte-v1.7.0.zip

11. Connect the 10-pin flat cable to the connector labeled APP (or BLE on hardware revision R3.2 and earlier).

    caution

    One of the wires on the flat cable between SEGGER J-Link and CHESTER has red color. This red color denotes signal number 1. This red-colored signal has to be oriented toward the black dot located next to the SWD connector on the CHESTER mainboard. The same rule with the cable applies at the side of SEGGER J-Link.

12. Flash the application firmware.

13. Disconnect the SEGGER J-Link adapter.

Nordic nRF9160 Modem Firmware

The procedure above flashes the HARDWARIO LTE modem firmware - the communication stack that connects CHESTER to HARDWARIO Cloud. That is a different image from the Nordic modem firmware (the baseband image, distributed as mfw_nrf9160_*.zip), which is the low-level cellular firmware of the nRF9160 SiP itself. The two images are flashed independently and with different commands.

Most deployments never need to touch the Nordic modem firmware. You need this procedure only when a specific network or SIM card requires a particular modem firmware version - for example a Vodafone Ukraine SIM card, which requires v1.3.7. See Tested SIM cards and operators.

caution

Flash a specific Nordic modem firmware version only when the operator or HARDWARIO support tells you to. Changing this image affects cellular behavior on all networks, not just the one you are troubleshooting.

The hardware setup, the Python virtual environment and the cabling rules are the same as in the Flashing Procedure above.

1. Download the modem firmware package from the nRF9160 download section at Nordic Semiconductor. Direct link for version 1.3.7: mfw_nrf9160_1.3.7.zip.

2. Open the CHESTER enclosure (6 screws from the bottom side) and connect SEGGER J-Link to the connector labeled APP (or BLE on hardware revision R3.2 and earlier).

   caution

   One of the wires on the flat cable between SEGGER J-Link and CHESTER has red color. This red color denotes signal number 1. This red-colored signal has to be oriented toward the black dot located next to the SWD connector on the CHESTER mainboard. The same rule with the cable applies at the side of SEGGER J-Link.

3. Activate the Python virtual environment with the HARDWARIO Command Line Tools and run this command to erase the application firmware:

   hardwario chester app erase

   tip

   The application firmware erase is required in order to prevent the reset signal collision between SEGGER J-Link and the application firmware.

4. Move the 10-pin flat cable to the connector labeled LTE.

   caution

   One of the wires on the flat cable between SEGGER J-Link and CHESTER has red color. This red color denotes signal number 1. This red-colored signal has to be oriented toward the black dot located next to the SWD connector on the CHESTER mainboard. The same rule with the cable applies at the side of SEGGER J-Link.

5. Run this command to flash the Nordic modem firmware:

   hardwario device nrf91 flash mfw_nrf9160_1.3.7.zip

   info

   Note the different command. hardwario device nrf91 flash writes the Nordic baseband image, while hardwario chester lte flash writes the HARDWARIO LTE modem firmware described above.

6. Move the 10-pin flat cable back to the connector labeled APP (or BLE on hardware revision R3.2 and earlier), flash the application firmware and disconnect the SEGGER J-Link adapter.

7. Configure the SIM card as usual - see SIM Card Setup. Flashing the Nordic modem firmware does not change the lte config parameters.