CMake Error: Error: generator : Ninja

After searching this forum, and on the internet, I do not find similar issue. So here is my question. I follow the docs at [1] and [2], attempting to build sel4 with commands

  1. git clone {sel4 github repo}
  2. mkdir build
  3. cd build
  4. cmake -DCROSS_COMPILER_PREFIX=x86_64 -DCMAKE_TOOLCHAIN_FILE=…/gcc.cmake -G Ninja -C …/configs/X64_verified.cmake …

But the error is thrown

CMake Error: Error: generator : Ninja
Does not match the generator used previously: Unix Makefiles
Either remove the CMakeCache.txt file and CMakeFiles directory or choose a different binary directory

Removing MakeCache.txt file and CMakeFiles directory doesn’t help either. The result remains.

I use Debian bookworm/sid, gcc 10.3.0, cmake 3.24.2, ninja-build 1.11.1-1, generate-ninja 0.0~git20220811.0bcd37b-1.

How should I build seL4? Thanks

[1]. Stand-alone seL4 builds | seL4 docs

[2]. Configuring and building an seL4 project | seL4 docs