# FAQs

## Common Build Problems and Solutions

###  "usr/sbin/ninja: invalid option -- w" Displayed During the Build Process

- **Symptom**

  The build fails, and **usr/sbin/ninja: invalid option -- w** is displayed.

- **Possible Causes**

  The Ninja version in use does not support the **--w** option.

- **Solution**

  Uninstall Ninja and GN, and [install Ninja and GN of the required version](../../device-dev/get-code/gettools-ide.md).

### "/usr/bin/ld: cannot find -lncurses" Displayed During the Build Process

- **Symptom**

  The build fails, and **/usr/bin/ld: cannot find -lncurses** is displayed.

- **Possible Causes**

  The ncurses library is not installed.

- **Solution**

  ```shell
  sudo apt-get install lib32ncurses5-dev
  ```

### "line 77: mcopy: command not found" Displayed During the Build Process

- **Symptom**

  The build fails, and **line 77: mcopy: command not found** is displayed.

- **Possible Causes**

  mcopy is not installed.

- **Solution**

  ```shell
  sudo apt-get install dosfstools mtools
  ```

### "riscv32-unknown-elf-gcc: error trying to exec 'cc1': execvp: No such file or directory" Displayed During the Build Process

- **Symptom**

  The build fails, and the following information is displayed: <br>**riscv32-unknown-elf-gcc: error trying to exec 'cc1': execvp: No such file or directory**

- **Possible Causes**

  You do not have the permission to access files in the RISC-V compiler directory.

- **Solution**

  1. Run the following command to locate **gcc_riscv32**:

  ```shell
  which riscv32-unknown-elf-gcc
  ```

  2. Run the **chmod** command to change the directory permission to **755**.

### "No module named 'Crypto'" Displayed During the Build Process

- **Symptom**

  The build fails, and **No module named 'Crypto'** is displayed.

- **Possible Causes**

  Crypto is not installed in Python 3.

- **Solution**

  1. Run the following command to query the Python version:

     ```shell
     python3 --version
     ```

  2. Ensure that Python 3.9.2 or later is installed, and then run the following command to install PyCryptodome:

     ```shell
     sudo pip3 install pycryptodome
     ```

### "xx.sh : xx unexpected operator" Displayed During the Build Process

- **Symptom**

  The build fails, and **xx.sh [: xx unexpected operator** is displayed.

- **Possible Causes**

  The build environment shell is not bash.

- **Solution**

  ```shell
  sudo rm -rf /bin/sh
  sudo ln -s /bin/bash /bin/sh
  ```