I have tested my link cables and GC adapters very thoroughly and I have
bad news! Here is what we are looking at:
A K1 GBA SP from k1gba.com. PID 00610603 PSN 120614 . A 1st gen GBA SP. An orange GBA Taco.
With all of these you can boot without a cart inserted or hold start+select when booting a game to boot without the Nintendo logo. A normal GBA will be ready to receive code to boot from the port labeled EXT. WIth the K1 GBA the option to show the GBA splash screen must be enabled for this feature to be feasible. I have not tried the link cable features with the K1's emulators yet. I more just wanted to play multiplayer and co-op GBA games such as Kirby and the Amazing Mirror.
"Joytech GBA SP Earphone Adapter with stereo earphones. Enjoy Dynamic stereo sound from your GBA SP."
works
MadCatz cable. Mine looks like the one pictured but with the silvery color of
this instead of purple. One end firmly affixes to the GBA and fits all three GBAs. The other end has a GC adapter and a GBA link. There is a switch in the middle that switches between the two modes.
does not work
Pelican 4 Player GBA link cable. Has a switch in the center to switch between GBA and GB modes.
does not work
Nyko GBA GC adaptor. It is so big that it does not really fit the GBA SP as it presses down on L and R. Miraculously it fits the K1 GBA SP since its shoulder buttons are smaller.
does not work
Headphone Adapter test
I have to press * + Left to switch from TV-out mode back to the screen. The stereo audio works and sounds excellent.
Mario Kart Single-Pak test
With the MadCatz cable, no luck. With the Pelican cable it only worked in the case of the GBA SP or GBA Taco running the pak and
the K1 GBA had to be in Player 3's slot. If the K1 was in player 1 or 2's position it wouldn't work. The K1 GBA SP could not be the GBA with the pak sending it to players 2 and 3; it wouldn't work.
Any scenario where the K1 was player 1 or 2 wouldn't work.
Mario Kart Multi-Pak test
Unsuccessful. Very bad. I might try later and it might be related to the player 3 only thing. But as I only have one real cart of Mario Kart for now I'm not going to test beyond 1 real cart and 1 rom.
Four Swords Adventures Gamecube test
With all three link cables the GBA SP and GBA Taco booted no problem. You can do this any time the game is running.
With all three link cables in any player slot
the K1 GBA SP would not boot the four swords loader. This happened when turning it on with no game inserted, when start+select canceling a a real game from booting, and when canceling a rom from booting.
Tests Worth Trying
- The Sonic Adventures/Advances Chao tests
- The Tingle Tuner Tests (There is a ROM available for the Tingle Tuner GC multiboot. It might work!)
- More 2 player carts.
- Bring the Gamecube GB player into the mix
Not worth trying:
FF Crystal Chronics: If 4 swords didn't work, see above
Four Swords GBA: how is this different from mario kart's test?
I would love for someone else to test with their own accessories, preferably first party ones. I don't consider my results conclusive but I doubt they are isolated. It can't just be that 1st party accessories are all you can use because they are not too different physically and they are almost impossible to find today. I think the K team very much needs to test their own devices and consider rolling out a firmware update. I would love to hear from Another World, Maxzhou, or the K1 team about these issues too.