px4_fmu-v2 cannot be the first argument.

[yiwc]

Describe the bug
Making procedure was ok.
Today after somehow change of release by using
git checkout v1.8.1 or git checkout v1.9.0-alpha
then when I use
make px4_fmu-v4_default
or
make px4_fmu-v2_default
I meet make fail error:
evan@EvanUbuntu16:~/src/Firmware$ make px4_fmu-v2 Makefile:378: *** "px4_fmu-v2 cannot be the first argument. Use 'make help|list_config_targets' to get a list of all possible [configuration] targets."。

This error also happens with v4:
evan@EvanUbuntu16:~/src/Firmware$ make px4_fmu-v4_default Makefile:378: *** "px4_fmu-v4_default cannot be the first argument. Use 'make help|list_config_targets' to get a list of all possible [configuration] targets."。

although It works with make posix,with making successful result.

I meet this problem on various computers, while dealing with versions. And can't find a way to repair this problem.

Expected behavior
Make successful as before.

Additional context

What the problem with this? and what's the supposed operation to change the firmware version?
Thanks for your team's work!

[TSC21]

That command only works for upstream master. Use make px4fmu-v2_default - https://dev.px4.io/v1.8.2/en/setup/building_px4.html.