That's good. 
Unfortunately, the only way to find the answer is to test with your PC.
Because there might be so many cases of failure to build, so it's hard to tell you the exact cause of the build failure.
And I also DEEPLY thank you for your interest in our webOS OSE project.
GOOD JOB! Now you can exclude testapps from img file.
by editting
/build-webos/meta-webosose/meta-webos/recipes-core/packagegroups/packagegroup-webos-extended.bb
Plus, there were many errors occurred with various environment. i tried to fix them, but failed...
All that i want to tell you is,
there might be so many cases of failure to build with YOCTO.
but if you try update and re-building, re-packaging,
Yocto is best tool for you.
All right! Thanks to your help, I was able to build. thank you!
Have a nice day! 
As you advised...
I'm using YOCTO now, but I'm getting a lot of errors.
But this situation is interesting to me! 
Thanks for your help and I will definitely use YOCTO to complete the project development! 
I forward the reply to your question from our dev. team. Please check the below comments.
We have fixed the issue to show the app list up to date in the Home Application when the user executes the restart sam in the SSH.
Note: In our case app was successfully removed by com.webos.appInstallService/remove but the removed app is still showing in the Home Application when the user executes the restart sam in the SSH.
When the restart sam command executes in the SSH, the com.webos.service.applicationmanager/listLaunchPoints method responds in the onFailure callback, so the Home application invokes the method again to get the latest application list.
I'll send your snippet to the developer. It might take some time.
Thank you so much. 