Development for original Instinct devices

I have the original Instinct Solar and Instinct Tactical devices. I have looked everywhere to see if it is even possible to develop for these devices. It appears that they are not supported in the SDK's devices list. Is it possible to just build for say the instinct 2 or something and have it work? If so, I also cannot find info on side-loading a program on older devices without an apps folder even if I could compile one. I just want to make a really simple custom widget for them. I am fairly new to this whole thing. Any advice would be appreciated. Thanks.