Another comment mentions it, but it is PalmOS 5, which already ran on ARM devices. Some of them 400MHz+ ARM chips like various Intel XScale models: https://en.

Another comment mentions it, but it is PalmOS 5, which already ran on ARM devices. Some of them 400MHz+ ARM chips like various Intel XScale models: https://en.wikipedia.org/wiki/Palm_Tungsten https://en.wikipedia.org/wiki/Palm_Tungsten So I imagine it was already pretty snappy on those devices. I think the RP2040 might be a downgrade in comparison...the clock speed at least, is much lower.