To cross compile, the rust tool chain for armv5te-musl needs to be installed

rustup target add armv5te-unknown-linux-musleabi

To tell rust to compile for armv5te-musl by default and to set the correct linker include the following in .cargo/config.toml

[build]
target = "armv5te-unknown-linux-musleabi"

[target.armv5te-unknown-linux-musleabi]
linker = "rust-lld"

See https://crates.io/crates/ev3dev-lang-rust for information about cross compiling your code

Enabling global lto causes more aggressive dead code elimination

Setting strip to true removes debugging information from the binary

[profile.release]
lto = true
strip = true