You haven't listed any reason why you'd absolutely need to make a FlashApp, rather than an ASM program
On the TI-68k series, FlashApps have never been popular, because of at least three reasons:
* the toolchain sucks, to begin with. The TIFS IDE is slow and buggy, the embedded emulator is a joke, and the C compiler is buggy and often generates bad code;
* FlashApps needed (free of charge) signing by TI. At some point, AFAWCT, they quit responding to signing requests. The factoring of the public (validation) RSA keys, in 2009, made the community able to sign FlashApps on its own. However, by then, TI-68k programming in native code languages was already pretty much dead: the community belittled in 2006-2007 and never grew back up;
* on the TI-68k series, ASM programs have few annoying restrictions, unlike on the TI-Z80 series (which have less RAM and a small addressing space to begin with, so executing from Flash directly makes far more sense). Though TI instated an artificial restriction on the size of ASM programs and Exec strings in AMS 2.xx, it is laughably easy to work around, and it was effectively disabled by TI on the 89T.
ASM programs can do almost everything users and programmers need, including full-blown event-driven programs (not popular, but possible), a number of event hooks, various RAM-resident programs for expanding functionality (so-called "kernels").
FlashApps are the recommended way to perform deep OS integration, the likes of making your own language localizations, or providing multiple TI-Basic extensions in the namespace of the FlashApp. They execute from Flash, so they take less RAM when they're executing.
But I strongly doubt you need or want to do deep OS integration, and there's usually plenty of RAM... As such, I'd simply recommend making ASM programs
GCC4TI has more features, more optimizations and fewer bugs than the dead TIGCC. Of course, I'm biased, but I'm nevertheless stating facts