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A constant current load for testing your projects. 6 amps, 60 volts and 25 watts in a workbench-friendly package with a USB interface.
A constant current load for testing your projects. 6 amps, 60 volts and 25 watts in a workbench-friendly package with a USB interface.
361 backers pledged £24,270 to help bring this project to life.

Upgrading your Re:load Pro firmware

Posted by Nick Johnson (Creator)

Some of you have started receiving your Re:load Pros already! Since the firmware is evolving rapidly, the firmware on the device you received is already not the latest version. Later updates make several improvements, including adding support for undervoltage cutoff, and improved calibration routines.

To install the firmware updates, you'll need Python 2.7 and pip. Then, you'll need to install the 'cyflash' package, like so:

    pip install cyflash

You'll also need to download the latest firmware. As of this writing, that's version 1.4, which can be found here. The latest firmware will always be available on the Arachnid Labs site.

Once cyflash is installed, plug your Re:load Pro into your computer and identify what device it shows up as. On linux and mac, it will show up as something like /dev/tty.usbserial-somenumbers. On Windows, it will show up as a COM port, which you can identify using Device Manager.

Next, you need to put your Re:load Pro into upgrade mode. Press the encoder button to enter the menu, then scroll down until you see "Upgrade Mode". Highlight that and press the encoder button again.

Now that you have the firmware and know how your Re:load Pro has identified itself to your OS, you can issue the update command:

    cyflash --serial device "Reload Pro v1.4.cyacd"

Replace 'device' with the name of your USB device, and the filename with the filename of the latest firmware version.

Cyflash will then upload the latest firmware, and your Re:load Pro will reboot. It should show the new firmware version number on the boot screen. Congratulations!

Kean, Daniel Fikes, and 2 more people like this update.


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    1. Nick Johnson 2-time creator on

      For anyone who's been having calibration issues, I've released a new firmware revision that ought to improve these a lot. You can get version 1.5 here:

    2. Nick Johnson 2-time creator on

      @serge yes, absolutely! If you have an SWD programmer such as the Miniprog3, you can solder a header inside the r:lp and program it that way. Otherwise, you can click on tools -> Bootloader host.

    3. Missing avatar

      Serge Tremblay on

      Hi Nick, I'm waiting for my Re:Load Pro hopefully this week and I'm very excited about this product. Can we use PSoC Creator to upgrade the firmware ? If yes how to ?

    4. Nick Johnson 2-time creator on

      @brian I haven't been keeping a complete changelog for existing versions, but 1.4 and onwards will have one, as well as tags in the GitHub repository.

      @jasse you can install Python and pip on any of those platforms in order to use it to upgrade your firmware.

    5. jasse

      The Python and Pip software, should they be run under Linux, Windows or Mac ???

    6. Missing avatar

      brian r on

      Is there a listing of the changes in the firmware between versions? Something that could let us know if a particular version is worth loading?