The step when you first do this:
repo sync
Hi wenfu ,
You have not mentioned which BSP version you are using. you can refer section 5.6.5 Restarting a build environment of i.MX Yocto project User's guide of respected version which you are using. For reference we have attached L4.14.98_2.0.0 version's i.MX yocto project user's guide.
So in your case you can give below command and then build image using $ bitbake xxx command.
$ source setup-environment build-xwayland
Regards,
Radhika Somaiya.