.elf generation trouble in Firmware V1.6.5 with make target of px4fmu-v2_default

Hi all:
I got a trouble when built px4fmu-v2_default to generate .elf file.
I got hard fault frequently when I add SPI and I2C sensors to my pixhawk. So I wanna analyze it with arm-none-eabi-gdb by the PX4 dev guide:https://dev.px4.io/en/debug/gdb_debugging.html.
However, I CAN’T FIND the .elf file as the guide said:
arm-none-eabi-gdb build/px4fmu-v2_default/nuttx_px4fmu-v2_default.elf
even in the hole Firmware folder. I tried to change defconfig in Firmware/nuttx-configs/px4fmu-v2/nsh:
# CONFIG_ELF is not set → CONFIG_ELF=y
and rebuilt the target, but the .elf file still not generate.
Is the guide out of date, or I missed any step? I just want to debug the hard fault. Very appreciate your help.

The post seems to be submerged.T_T

Nobody use gdb_debugging? It’s a big problem.

Did you tried with