Already possible even on non-jailbroken devices! There is a neat JavaScript-based web emulator for TI-84 Plus ROMs. Works on PC and smartphones. HOW TO GET A TI-84 PLUS C SILVER EDITION WORKING ON ANY SMARTPHONE: Download this image into your phone's photo gallery. This image has the calculator's ROM file encoded (the website cannot legally host the ROM). Visit https://www.cemetech.net/projects/jstified/ on Safari (you CAN use Chrome, however I find Safari to be a ton faster, like a real TI-84 Plus) When the website loads, scroll to the right and read the terms of use (lol). Click the button that accepts them. Then, press the "Choose File" button and select the image you just downloaded. This will freeze the screen for a second as it loads up the ROM. Press the virtual calculator's screen to start up the calculator. Voila! There is also another tool on the website called SourceCoder that should, theoretically, give you a "cloud" of sorts to put your calculator programs to access on your iPhone through jsTIfied. Unfortunately, I couldn't get it to work, but that may just be my own fault. For now, enjoy your free TI-84 Plus, even on unjailbroken devices!