CEleste VS CEmu

Nope. I'm the author of the port, and I converted the Lua code to C++ myself. The calculator is way too slow to run a GBA emulator. If you want to take a look at the code, it's available here: https://github.com/commandblockguy/CEleste

I would need a few more zeros to motivate me to do this, but one viable approach I'll throw out there is use CEmu to validate equations. From the math side, you can start with the real equation, transform, approximate, and invert approach. For instance, for certain types of simple line drawings you can turn them into equations by: (on a real computer)

There are various cross-platform ways, I'm surprised you haven't found them (although ticalc.org probably doesn't have updated info so I guess that could explain it): TiLP (see my fork herefor Mac binaries directly) has a rom-dumping feature which produces a *full rom dump, and CEmu's dumper (which dumps less things but enough to emulate the calc, on which you can transfer missing things if needed, like apps). Since you're I retested in emulation you might want to go with CEmu (take the nightly build not the release) and follow the steps.

Unless taking screenshot via TI-Connect CE counts, you can't on a physical calculator. If you use an emulator like CEmu then it's really easy: https://github.com/CE-Programming/CEmu

The main branch of CEmu does not bring over any user data. There's a USB branch which will let you send apps and programs as if there were a USB port connected to it. You'll have to build it yourself but I'm pretty sure it's this branch: https://github.com/CE-Programming/CEmu/tree/feature/libusb

I would recommend the fx-9750giii. It's affordable. It's very interesting. And honestly, if you can find the roms for TI calculators, you can use CEmu to emulate the TI-84 CE.

For cemu the command seems to be -g , --settings Or maybe it's either. Not at my pc to test. More info here https://github.com/CE-Programming/CEmu/wiki/Command-Line-Arguments