Checkout and build custom rv32i-toolchain:
git clone --recurse-submodules --remote -b riscv32e-toolchain https://github.com/cathiele/rust.git
cd rust
./x.py build --target riscv32i-unknown-none-elf
Add custom toolchain to local rust installation:
rustup toolchain link riscv32i-toolchain $PWD/build/x86_64-unknown-linux-gnu/stage2
use custom toolchain in ch32v003-projects:
cd project-folder
rustup override set riscv32i-toolchain