Looks like it's only the new riscv variant.
Yes, as rust has built in support for riscv but not the Xtensa architecture that the other ESP chips use. There is esp-rs/rust fork that add support for these using a fork of llvm. So you can run rust on the other chips but need to build your own rust compiler do to so. Hopefully this work will be unstreamed someday but it could take a long time to do that.
Actually you don't need to build your own. The rust on esp project provide a espup tool that downloads a pre built toolchain for Xtensa.
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