How can I let the phonemizer know about a new language that I added to eSpeak-ng

[isolveit-aps]

I'm trying to train piper tts on a new language. I already added the Faroese (FO) variant to eSpeak-ng, but that version is not the one that gets downloaded when I install espeak-ng in colab or on my local virtual environment. When I try to use piper_phonemize in those environments, the response is just: Failed to set eSpeak-ng voice. This happens, regardless of the fact that I installed espeak-ng on that machine, using the espeak-ng version that supports Faroese. (I cloned it from the github repo commit for Faroese, and built and installed it on the colab environment).
So my question is: how can I let piper_phonemize know about it, so that I don't run into this error, when I try to get phonemes on my faroese dataset:

espeak-ng works with faroese, as shown - but piper_phonemize doesn't recognize it: