is the pizero fba image using pifba?
No, it is using fba-libretro.
ive tried to get to the command line to update and install my own packages but it boots right back to AM. im sure theres a setting somewhere or a way to go into the terminal... how does one go about that?
It is not possible, the image is built using buildroot, they are no package manager available. If you want to get your hand dirty you have to clone the git repository and rebuild the entire image. It is not very complicated, but it requires a bit more knowledges.
is there a proper shutdown method from AM?
No, this image is made initially for arcade machines that I shutdown by cutting the power off ... This is why the image is readonly and it should be safe to power it down this way.
Thanks for your support. I take the opportunity to give you some updates (and tell you a bit about my life). I'm trying to make a very tiny business building arcade machines, that's why I developed those images. But I also need hardware stuff so I'm not 100% on those.
Anyway a new version should come on next month, I kept all your emulator requests, I'll try to add them (there should be no issues). Currently I'm trying to focus on playable N64 emulation.