Hello Jianxin,
I would need to ask you to please open a Case requesting the schematic in .brd format. I don’t know why it wasn’t made available with the rest of the Design Files, thanks for bringing this up to our attention!
Regards,
Hello Jianxin,
You can open a Case by following the instructions on the following document:
https://community.nxp.com/docs/DOC-329745
Regards,