Downloading Epsilon from NumWorks' website

Epsilon source code is partially available, with restrictions (strong copyright, e.g. with limited rights about redistributions) at numworks/epsilon on GitHub.

You can run it using the build instructions they give on their website, with all the restrictions about custom firmwares.

If you want the full binary with kernel and bootloader, you need to get it from NumWorks website as they're signed and source isn't even available. Here are the requirements:

• A NumWorks account (downloading won't work without it)
• An internet connection
• Knowing the model name for which you want the firmware

Download options

You can find the models by reading the source code of their website (it's not really obfuscated) or simply guessing from the model names. Here is a list of the models we know:

• n0100
• n0110
• n0115
• n0120
• N0120_PORTUGAL_PROTOTYPE_20210930

Additionally, you can choose to download either the stable or beta version, named stable and beta.

Downloading

To download, first log in to NumWorks website as usual (you aren't required to use a browser with WebUSB support, Firefox works fine). Once you are logged in, simply open https://my.numworks.com/firmwares/$MODEL/$VERSION.dfu, replacing the values with the version you want, and save the file.

For example, to download the release for stable N0110, you would download from https://my.numworks.com/firmwares/n0110/stable.dfu.

If you get an error "401. Unauthorized.", make sure you are logged into your account.

Note that account cookies doesn't expire (my 2 years ago cookie still works), so it's perfectly fine to pass them as simple headers in curl.

Version info

When scripting and bulk downloading from the website, it can be useful get a few metadata. You can do so using 2 different ways:

• Extracting metadata from the binary by hand
• Downloading metadata from NumWorks website, avoiding implementing more complex extraction, and can be done before downloading the binary

On this page, we'll cover the second way, downloading from their website. The syntax is similar to binary download, simply replacing .dfu with .json: https://my.numworks.com/firmwares/$MODEL/$VERSION.json

For stable N0110, you get https://my.numworks.com/firmwares/n0110/stable.json. At the time of writing, the reply is (formatted for easier reading):

{
  "id": 239,
  "version": "23.2.6",
  "patch_level": "22d1daa",
  "device_model": {
    "id": 2,
    "name": "N0110",
    "extension": "dfu"
  },
  "size": 3371357
}

Extracting internal and external flash

DFU files often need to be extracted before use (Upsilon Website can extract and flash DFU files, but it's not the case of most apps).

I don't have the time to rewrite a script (and I don't know the DFU format very well), but you can use the script from the downgrade documentation (used for N0110 unlocking, and work well).

The script work fine for N0110 and N0115. For N0120, you need to replace internal_size = 64 * 1024 by internal_size = 512 * 1024 (line 53, just after def unpack(fw):). For N0100, you need internal_size = 1024 * 1024.

The script will create internal.bin (bootloader) and external.bin (slots and kernel) files.

Once you got the files, you can whatever you want with them, like flashing them using the WebDFU, disassembling them (using Ghidra, for example) or simply extracting information.