@liam-
i know what the issue is. however, this means you're either going to haveta restart the game from the beginning, or start using save states. if you wanna do the first thing, and be able to save in-game (i STRONGLY reccommend this; i didn't do it and i think that's why i couldnt continue my game on the new patch) then follow these steps:
-open your emulator (hopefully VBA. i dunno how to do this in other ones).
-without opening a ROM, go to Options >> Emulator >> Save Type, and select Flash 128k instead of Flash 64k.
-now open your patched sienna rom, and press start on the title screen. the "1m sub-circuit" junk shouldn't appear at all anymore.
then just re-begin your game, and voila! :) your in-game saving will now work, as well as save states if you wanna use them. :)
however, if you've already tried this and it wouldn't workk, then i have noo idea. :/