Teracube appears to be fairly focused at environmentally conscious consumers. I am one of those. I myself am still using a Nexus 5, a phone that’s served me well for 7 years old at this point. And thus my interest has been tickled!
As far as sustainability is concerned, IME it is important to be able to obtain spare parts without having to ship the phone back and forth across the globe (think of the waste!). I’d much rather just order the replacement part itself and fix the phone myself. So the question is: what are your plans (if any) about making the spare parts available for purchase? If you have any – any plans to make them available past the 4 year “limited warranty” period?
(For context: I am still able to obtain a replacement battery for a Nexus 5, again, 7 years after its initial release, from third parties. I don’t anticipate to be true for a significantly more obscure phone that 2e will be. So, ultimately the only source of replacement parts will be Teracube itself.)
The other side of the coin is software. 3 years of software security updates does not make a phone any more significantly sustainable than other conventional phones on the market. Fairphone enables this kind of sustainability and reuse by making their android source tree, and thus the pre-requisite device drivers, public. It doesn’t look like it was done for the previous hardware released by yourselves, but maybe there are plans to publish the code for 2e?