Improve toolchain overriding documentation

README.md

@@ -57,11 +57,36 @@ No prerequisites are needed for macOS
 #### Installation commands
 
 ```sh
+git clone https://github.com/esp-rs/rust-build.git
+cd rust-build
 ./install-rust-toolchain.sh
 ```
-> Run `./install-rust-toolchain.sh --help` for more information about arguments.
 
 Export variables are displayed at the end of the script.
+> **Note**
+> If the export variables are added into the shell startup script, the shell may need to be refreshed.
+
+Installation of different version of toolchain:
+
+```
+./install-rust-toolchain.sh --toolchain-version 1.61.0.0 --export-file export-esp-rust.sh
+source export-esp-rust.sh
+```
+
+#### Arguments
+- `-b|--build-target`: Comma separated list of targets [`esp32,esp32s2,esp32s3,esp32c3`]. Defaults to: `esp32,esp32s2,esp32s3`
+- `-c|--cargo-home`: Cargo path.
+- `-d|--toolchain-destination`: Toolchain instalation folder. Defaults to: `<rustup_home>/toolchains/esp`
+- `-e|--extra-crates`: Extra crates to install. Defaults to: `ldproxy cargo-espflash`
+- `-f|--export-file`: Destination of the export file generated.
+- `-i|--installation-mode`: Installation mode: [`install, reinstall, uninstall`]. Defaults to: `install`
+- `-l|--llvm-version`: LLVM version.
+- `-m|--minified-esp-idf`: [Only applies if using `-s|--esp-idf-version`]. Deletes some idf folders to save space. Possible values [`YES, NO`]
+- `-n|--nightly-version`: Nightly Rust toolchain version. Defaults to: `nightly`
+- `-r|--rustup-home`: Path to .rustup. Defaults to: `~/.rustup`
+- `-s|--esp-idf-version`: [ESP-IDF branch](https://github.com/espressif/esp-idf/branches) to install. When empty, no esp-idf is installed. Default: `""`
+- `-t|--toolchain-version`: Xtensa Rust toolchain version
+- `-x|--clear-cache`: Removes cached distribution files. Possible values: [`YES, NO`]
 
 ### Windows x64
 
@@ -85,6 +110,8 @@ choco install cmake git ninja visualstudio2022-workload-vctools windows-sdk-10.0
 #### Installation commands for PowerShell
 
 ```sh
+git clone https://github.com/esp-rs/rust-build.git
+cd rust-build
 ./Install-RustToolchain.ps1
 ```
 
@@ -93,7 +120,7 @@ Export variables are displayed at the end of the output from the script.
 Installation of different version of toolchain:
 
 ```
-./Install-RustToolchain.sh --toolchain-version 1.61.0.0 --export-file Export-EspRust.ps1
+./Install-RustToolchain.ps1 --toolchain-version 1.61.0.0 --export-file Export-EspRust.ps1
 source ./Export-EspRust.ps1
 ```
 
@@ -125,6 +152,16 @@ rustup target add riscv32i-unknown-none-elf
 
     And `SERIAL` is the serial port connected to the target device.
     > [cargo-espflash](https://github.com/esp-rs/espflash/tree/master/cargo-espflash) also allows opening a serial monitor after flashing with `--monitor` option, see [Usage](https://github.com/esp-rs/espflash/tree/master/cargo-espflash#usage) section for more information about arguments.
+
+    When building for Xtensa targets, we need to [override the `esp` toolchain](https://rust-lang.github.io/rustup/overrides.html), there are several solutions:
+      - Set `esp` toolchain as default: `rustup default esp`
+      - Use `cargo +esp`
+      - Override the project directory: `rustup override set esp`
+      - Create a file called `rust-toolchain.toml` or `rust-toolchain` with:
+        ```toml
+        [toolchain]
+        channel = "esp"
+        ```
 #### Idf first approach
 
 1. Get example source code