Hello @liuqimin ,
I think it is something related to Matlab 2020b. Typically we use a Data Store Memory for Variables that are going to be used in FreeMaster. But for easy access from FreeMaster to the variable address from elf file, we set the storage class of the Data Store Memory either to Volatile or Exported Global.
The thing is that I don't see that option anymore in the Data Store Memory on R2020b so we have to investigate this with MathWorks.However, in the Data Store Memory documentation, the option "Storage class" seems to be available. https://www.mathworks.com/help/simulink/slref/datastorememory.html

Maybe I am missing something... Can you please send me the generated code and the model?
Regards,
Marius