One tip is to use GPLv3, which would force the users of your code, who would put the software on their hardware, to make it possible for their users to reflash the devices. For everyone who doesn't want to allow that you could offer a commercial license.
This way of open sourcing works quite well for example for the Qt Company, they sell commercial licenses to automobile companies which don't want people to reflash their in vehicle infotainment systems for some reason, so they pay a per device commercial license. The Qt Company takes the money and pays developers to keep on working on the free software version of Qt which is GPLv3.
Kind of win win for everyone, small users who play with the sofware on their raspberry pi get the source code and big companies with their own propriatary hardware would pay licenses.
One tip is to use GPLv3, which would force the users of your code, who would put the software on their hardware, to make it possible for their users to reflash the devices. For everyone who doesn't want to allow that you could offer a commercial license.
This way of open sourcing works quite well for example for the Qt Company, they sell commercial licenses to automobile companies which don't want people to reflash their in vehicle infotainment systems for some reason, so they pay a per device commercial license. The Qt Company takes the money and pays developers to keep on working on the free software version of Qt which is GPLv3.
Kind of win win for everyone, small users who play with the sofware on their raspberry pi get the source code and big companies with their own propriatary hardware would pay licenses.