west flash to teensy 41 fail, use blinky with west build

[WolsYang]

I follow the Getting Started Guide, then

1. zephyrproject\zephyr>$ west build -p auto -b teensy41 samples\basic\blinky
2. zephyrproject\zephyr>$ west flash <<Fail
3. zephyrproject\zephyr>$ cd build
4. zephyrproject\zephyr\build>$ west flash <<Fail
5. zephyrproject\zephyr\build>$ ninja flash <<Fail
   Here is the error message show in windows10 cmd :
   [0/1] Flashing teensy41
   -- west flash: rebuilding
   ninja: no work to do.
   FATAL ERROR: either a pristine build is needed, or board teensy41 doesn't support west flash/debug (no ZEPHYR_RUNNERS_YAML in CMake cache)
   FAILED: zephyr/cmake/flash/CMakeFiles/flash C:/Users/canic/Desktop/zephyrproject/zephyr/build/zephyr/cmake/flash/CMakeFiles/flash
   cmd.exe /C "cd /D C:\Users\canic\Desktop\zephyrproject\zephyr\build && "C:\Program Files\CMake\bin\cmake.exe" -DTARGET=flash -DDEPENDENCIES="" -P C:/Users/canic/Desktop/zephyrproject/zephyr/cmake/flash/check_runner_dependencies.cmake && "C:\Program Files\CMake\bin\cmake.exe" -E env C:/Users/canic/AppData/Local/Programs/Python/Python39/python.exe -m west flash"
   ninja: build stopped: subcommand failed.

Is any step I do it wrong?

[galak]

Nothing wrong, the board doesn't support west flash/debug. There is no board.cmake describing how to invoke the west runners for flashing purposes.