Sorry for the huge delay in answering. Now that both the exams and the heatwaves are over, I have some time to answer.
My main goal is to have a working device with nothing sticking out of it. Ideally, this means reverting it to its original boot loader, which is almost impossible to achieve.
The second option is to have a stable version of le running on it. But the stable version of le does not contain the wireless driver because its wifi chip is... realtek, so I have to resort to powerline if I chose that solution. That is the current status, now that I made it boot from usb.
Third option is to use one of your images, since they do contain the driver. But that means using a dev version of le, and very frequent updates.
If you consider that I want to use it as an iptv device only, I think I have done too much for it but I haven't forgotten anything.