After seeing a huge difference in terms of screen size from the last version of ZodTTD's gpSPhone v0.1.5, the developer has released the latest version of this GBA emulator for Apple's iPhone and iTouch with gpSPhone v0.5.0. This latest version takes care of improving the application's general performance, as well as updating the format for its games' save states.

ZodTTD also answered one of the more frequently asked questions about the homebrew application concerning the correct bios used when running gpSPhone v0.5.0:

If you have md5sum you can check if it has this hash: a860e8c0b6d573d191e4ec7db1b1e4f6
that BIOS should work fine. I think that some others work fine too, although I haven't confirmed this with absolute certainty. It's also theoretically possible to use custom (and free) BIOS replacements,
but I don't know of any publically available ones.

This is particularly important since the application was based from Exophase's gpSP homebrew for the PSP. Anyway, here's the change log for this version of gpSPhone v0.5.0:

*Considerable performance increase due to moving to Exophase's dynarec.
*Considerable compatibility increase due to moving to Exophase's dynarec.
*Save states format has been updated! Old save states most likely won't work!