# Make px4fmu-v2\_default error **URL:** \ **Category:** Uncategorized\ **Created:** [March 23, 2018, 7:33am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129 "2018-03-23T07:33:31Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![daxia](https://discuss.px4.io/letter_avatar_proxy/v4/letter/d/ec9cab/32.png) [@daxia](https://discuss.px4.io/u/daxia)\ **Post date:** [March 23, 2018, 7:33am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/1 "2018-03-23T07:33:32Z")
i need help ,please. mj@mj-Lenovo-G470:~/px4/src/Firmware$ make px4fmu-v2\_default – CMAKE\_MODULE\_PATH: /home/mj/px4/src/Firmware/cmake – Nuttx build for px4fmu-v2 on m4 hardware, using nsh with ROMFS on px4fmu\_common – Build Type: MinSizeRel – PX4 VERSION: v1.6.5 – CONFIG: nuttx-px4fmu-v2-default – The ASM compiler identification is GNU – Found assembler: /home/mj/gcc-arm-none-eabi-5\_4-2016q2/bin/arm-none-eabi-gcc – Found PythonInterp: /usr/bin/python (found version “2.7.12”) – Found PY\_jinja2: /usr/lib/python2.7/dist-packages/jinja2 CMake Error at CMakeLists.txt:332 (STRING): string sub-command REGEX, mode MATCH needs at least 5 arguments total to command. – C compiler: CMake Error at CMakeLists.txt:340 (STRING): string sub-command REGEX, mode MATCH needs at least 5 arguments total to command. – C++ compiler: – Adding ROMFS on px4fmu-v2 – Nuttx build for px4fmu-v2 on m3 hardware, using nsh – Configuring incomplete, errors occurred! See also “/home/mj/px4/src/Firmware/build\_px4fmu-v2\_default/CMakeFiles/CMakeOutput.log”. /bin/sh: 1: cd: can’t cd to /home/mj/px4/src/Firmware/build\_px4fmu-v2\_default Makefile:164: recipe for target ‘px4fmu-v2\_default’ failed make: \*\*\* [px4fmu-v2\_default] Error 2 mj@mj-Lenovo-G470:~/px4/src/Firmware$ ---
**Author:** ![acfloria](https://discuss.px4.io/user_avatar/discuss.px4.io/acfloria/32/1568_2.png) [@acfloria](https://discuss.px4.io/u/acfloria)\ **Post date:** [March 23, 2018, 7:52am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/2 "2018-03-23T07:52:42Z")
With the current master you should use a never gcc version: GCC 7-2017-q4 Maybe the old version causes that problem. ---
**Author:** ![daxia](https://discuss.px4.io/letter_avatar_proxy/v4/letter/d/ec9cab/32.png) [@daxia](https://discuss.px4.io/u/daxia)\ **Post date:** [March 25, 2018, 2:04am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/3 "2018-03-25T02:04:55Z")
But i have read a topic in which LorenzMeier said “You have GCC 6 but we’re only supporting versions up to GCC 5 right now. You can install GCC 5 from here: [http://dev.px4.io/starting-installing-linux-boutique.html#toolchain-installation80](http://dev.px4.io/starting-installing-linux-boutique.html#toolchain-installation80)”.So ,are you using the gcc version 2017 ? And dose it work ? ---
**Author:** ![acfloria](https://discuss.px4.io/user_avatar/discuss.px4.io/acfloria/32/1568_2.png) [@acfloria](https://discuss.px4.io/u/acfloria)\ **Post date:** [March 29, 2018, 6:08am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/4 "2018-03-29T06:08:36Z")
See the updated [dev guide](https://dev.px4.io/en/setup/dev_env_linux_ubuntu.html). It changed approximately two month ago and now you need the newer GCC version. I am using the one specified in the dev guide and it works for me. As PX4 is still in development the tool chain can change from time to time. ---
**Author:** ![daxia](https://discuss.px4.io/letter_avatar_proxy/v4/letter/d/ec9cab/32.png) [@daxia](https://discuss.px4.io/u/daxia)\ **Post date:** [March 30, 2018, 3:29pm UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/5 "2018-03-30T15:29:44Z")
thank you very much.i appreciate your reply.and it did make a little progress,but still report errors like this: [14%] Built target nuttx\_patch\_px4fmu-v2 [14%] Built target nuttx\_configure\_px4fmu-v2 [14%] Building NuttX for px4fmu-v2 with nsh make[4]: warning: jobserver unavailable: using -j1. Add ‘+’ to parent make rule. stdio/lib\_sscanf.c: In function ‘vsscanf’: stdio/lib\_sscanf.c:419:28: error: this statement may fall through [-Werror=implicit-fallthrough=] sign = true; ^ stdio/lib\_sscanf.c:420:21: note: here case ‘u’: ^~~~ cc1: all warnings being treated as errors make[5]: \*\*\* [bin/lib\_sscanf.o] Error 1 make[4]: \*\*\* [libc/libc.a] Error 2 src/modules/px4iofirmware/CMakeFiles/nuttx\_export\_px4io-v2.dir/build.make:60: recipe for target ‘px4io-v2/nuttx\_export.stamp’ failed make[3]: \*\*\* [px4io-v2/nuttx\_export.stamp] Error 2 CMakeFiles/Makefile2:8527: recipe for target ‘src/modules/px4iofirmware/CMakeFiles/nuttx\_export\_px4io-v2.dir/all’ failed make[2]: \*\*\* [src/modules/px4iofirmware/CMakeFiles/nuttx\_export\_px4io-v2.dir/all] Error 2 make[2]: \*\*\* 正在等待未完成的任务… stdio/lib\_sscanf.c: In function ‘vsscanf’: stdio/lib\_sscanf.c:419:28: error: this statement may fall through [-Werror=implicit-fallthrough=] sign = true; ^ stdio/lib\_sscanf.c:420:21: note: here case ‘u’: ^~~~ cc1: all warnings being treated as errors make[5]: \*\*\* [bin/lib\_sscanf.o] Error 1 make[4]: \*\*\* [libc/libc.a] Error 2 CMakeFiles/nuttx\_export\_px4fmu-v2.dir/build.make:60: recipe for target ‘px4fmu-v2/nuttx\_export.stamp’ failed make[3]: \*\*\* [px4fmu-v2/nuttx\_export.stamp] Error 2 CMakeFiles/Makefile2:1633: recipe for target ‘CMakeFiles/nuttx\_export\_px4fmu-v2.dir/all’ failed make[2]: \*\*\* [CMakeFiles/nuttx\_export\_px4fmu-v2.dir/all] Error 2 Makefile:160: recipe for target ‘all’ failed make[1]: \*\*\* [all] Error 2 Makefile:164: recipe for target ‘px4fmu-v2\_default’ failed make: \*\*\* [px4fmu-v2\_default] Error 2 ---
**Author:** ![xiaofyao](https://discuss.px4.io/letter_avatar_proxy/v4/letter/x/eb8c5e/32.png) [@xiaofyao](https://discuss.px4.io/u/xiaofyao)\ **Post date:** [April 28, 2018, 8:42am UTC](https://discuss.px4.io/t/make-px4fmu-v2-default-error/6129/6 "2018-04-28T08:42:42Z")
I’ve met the question as you too. Have you worked out any approach to solve the problem?