Ha! I haven't even announced 5.1 yet, my friend
I saw this on your github, about two hours ago, I hope I didn't do anything stupid, by posting the news, if so don't hesitate to tell me, I must admit that I behaves a bit like a crazy puppy when I see something new!
Anyway, for the RCA Studio II stuff, you really need to use BOTH controllers - so the best way to do that is to map one of the NDS keys to 'SWITCH' which will swap P1 and P2 keypads on-the-fly. This way, you can toggle easily between the A and B controllers of the Studio II.
Thank you for this tip my friend, by digging a little, I actually realized that the two controllers were necessary, I was trying to find a way by juggling the left/player1, right/player2, dual action A and dual action B but I hadn't thought of mapping a ds key to "SWITCH"
To be honest, I'm just learning my way around the system as well... To get full resolution on the Intellivision, a hacked bit of hardware is needed to expand the GRAM (Graphics RAM) from 0.5K to 2K which makes for a very non-standard Intellivision (and some classic games which rely on the quirks of a 0.5K GRAM will not look right). But Decle is a master Intellivision programmer and has decided to play around with this 2K GRAM intellivision and (mostly because it looked neat), I decided to support this with the latest Nintellivision build.
Not knowing at all, I googled "Decle's 2KGRAM" and I came straight to his topic on AtariAge, I said to myself "no doubt, this is where it's happening!"
And yes, the new 2K GRAM experimental build is designed to play the RCA Studio II emulator and the new "Chippie" Chip-8 emulator done by Decle for the Intellivision (Chippie just came out last week). I'm going to find a way to integrate the experimental build into the main build - but it's tricky.
For now, however, this special 2K GRAM build is a separate build - but both the official Nintellivision build and this special 2K build can co-exist nicely on the same DS. I'm going to look into combining the functionality in the future.
I installed both without any problem, I put the .nds in two different directories, one called Intellivision and the other RCA Studio 2 in order to separate them, especially when I landed in my Roms directory but even without that , actually the two coexist very well.
In any case, thank you for all these explanations as well as for all your work, it’s really great!