I already asked this in an old thread, but it seems that went unnoticed. I'm curious about the legality of using something like the hyperkin retron sq with an official game cartridge. Does the hyperkin affect viability of the run in any way?

I'm also going to ask this in the metroid 2 speedrun forum. Unless someone here would also know about that. Cause I want to speedrun off my official Metroid 2 cartridge rather than on emulator.

I also want to note, that I have no issues proving I'm using an official copy rather than a rom loaded onto a micro SD.

If I recall correctly, the Retron SQ just dumps the contents of the cartridge and runs it through an emulator.

Two issues arise: the emulator Hyperkin products run is pretty much unauditable for accuracy, the other being that for sure Hyperkin doesn't bundle the GBA BIOS into the console for copyright reasons, which means that it's automatically banned for RTA timings because the emulator is going to use reverse engineered (and faster) default routines rather than the ones coming from the BIOS, potentially giving an unfair advantage versus people using Bizhawk w/a BIOS dump or actual hardware.

Are there any affordable options that just play the games? Like I said before, I just need something that will allow me to connect to my recording device. Unfortunately, I can't find the GBA player for GCN at a price I can afford.

If you want to go down the real hardware route, GameCube + GBPlayer would be the cheapest way to play comfortably (NTSC-J consoles are readily available, at least here in Europe and can be modded to be NTSC-U by moving a resistor on the motherboard).

Cost cutting measures might be installing PicoBoot on the GC (soldering required) and using an SD2SP2 (microSD -> serial port 2, the latter is present only on the early GC models) so you won't need the GBPlayer boot disc since you can just fire up either GBI or a dump of the disc off the SD card.

To have digital output (namely, HDMI) out of the GC you'd have to fetch a GCVideo compatible dongle (uses the digital port present only on the earlier GameCube revision), which goes for anywhere from 35 to 50€ from the usual suspects such as AE, definitely more if you're buying locally. Remember that no NTSC versions of the GC output RGB.

Another solution might be modding a GBA (I don't think there's a kit out for the SP, yet) with one of the IPS screen + TV out kits, but you'd be bound to have a pile of AA batteries to run the console, plus not all TV out kits output HDMI, rather they output composite which got its obvious downsides.

Needless to say, the cheapest solution of them all is to run on the only approved emulator, as in Bizhawk using the mGBA core with a valid BIOS dump loaded. In that case you need only your own PC and a bare minimum OBS setup to record the emulator output and eventually the timer. Seeing your previous submissions that it seems you're on Linux, you can run Bizhawk on it too by installing mono and libgdiplus as requirements.

Ok, I managed to find a gcn gba attachment for relatively cheap, and I already know how to do decent enough HDMI adaption with that. I just need to put together my setup. One more question, do you know how the digiretro boy works? If it functions in the same way as the gba or does it work like the retron?

The DIGIretroBOY (aka Revo K101+) looks like an hardware clone and it seems that it packs also the original GBA BIOS.

Might be worth a shot running some test ROMs off the microSD adapter to evaluate whether it runs at the original framerate, especially considering that even the Analogue Pocket runs faster than a GBA as it stands (so again, only IGT can be submitted).