Well, the thread title asks the question, but I figure I'd explain why I think it could be possible before someone who knows what they're talking about comes in and sets me straight.
Basically, the GBA already has the hardware in it to function as a GB/C, right? It doesn't run gameboy games by emulation. I use both Nintendon't and GBARunner2 on the Wii and NDS/3DS (respectively) to run Gamecube and GBA games (also respectively) using the hardware that's already there.
We also know that some parts of the GB hardware are directly accessible from within GBA games - most notably, imo, is the hardware synth used to produce the gameboy's characteristic sound. GBA games can leverage those sound channels as well. (AFAIK these parts had to be carried along with the rest of the GBA hardware even when they dropped GB support because some games made use of it)
So, what is preventing a program from booting in GBA mode, then acting as a bootstrap for a game in GB/C mode? Is it something in the firmware that can't easily/realistically be circumvented? Or is the problem simply much more complex than I understand? [Actually, if we want to talk hypotheticals, wouldn't it have been neat if some GBA games had a built-in GB executable minigame in a similar manner to Luigi Bros. in NSLU?]
(Also I realize that I may have given this a misnomer, as instead of running in a limited mode on the GBA's main processor it would be outsourced to the dedicated hardware for GB/C games inside the console, but like, unless that's the direct source of my misunderstanding here I think it gets the point across well enough)
Basically, the GBA already has the hardware in it to function as a GB/C, right? It doesn't run gameboy games by emulation. I use both Nintendon't and GBARunner2 on the Wii and NDS/3DS (respectively) to run Gamecube and GBA games (also respectively) using the hardware that's already there.
We also know that some parts of the GB hardware are directly accessible from within GBA games - most notably, imo, is the hardware synth used to produce the gameboy's characteristic sound. GBA games can leverage those sound channels as well. (AFAIK these parts had to be carried along with the rest of the GBA hardware even when they dropped GB support because some games made use of it)
So, what is preventing a program from booting in GBA mode, then acting as a bootstrap for a game in GB/C mode? Is it something in the firmware that can't easily/realistically be circumvented? Or is the problem simply much more complex than I understand? [Actually, if we want to talk hypotheticals, wouldn't it have been neat if some GBA games had a built-in GB executable minigame in a similar manner to Luigi Bros. in NSLU?]
(Also I realize that I may have given this a misnomer, as instead of running in a limited mode on the GBA's main processor it would be outsourced to the dedicated hardware for GB/C games inside the console, but like, unless that's the direct source of my misunderstanding here I think it gets the point across well enough)