[pathless]

Remember AMD's Skybridge project? They wanted to put ARM and x86 together on one chip, but they cancelled it. I don't know why, because it seemed like a cool way to bridge the gap. Maybe they were worried it'd become a reverse trojan horse like the Apple Macintosh clones that came about shortly before Steve returned in the 90s.

Seeing as Raspberry Pi has no dog in the game, and simply wants to offer the best product possible, I wouldn't be surprised if this is their intentional way of giving people RISC-V with the intent to allow them time to port their code to it so they can eventually pull the ARM stack. I say this because Jeff Geerling has a video about the Pico 2 where he explicitly says you can only use RISC-V or ARM cores. Not both sets at the same time.

I think it's probably because a full migration to RISC-V would allow them to innovate a bit more and cut prices, although I don't know what the restrictions really are with ARM's IP control and pricing. At $5, every penny counts though.

[janice1999]

AMD also had a project to make ARM CPUs that would work with its AM4 x86 socket for Amazon (Project Seattle, replace by Amazon's in-house Graviton). I see the Pico2 in a similar light. If customers want ARM or RISC-V Raspberry Pi has them covered. if the market moves away from ARM, they'll be well positioned.

[soneil]

You can use both at the same time, but you can only use two cores. eg 2xARM, 2xRV, or one of each.