A variant will define hundreds of features. Use BUILDROM, to build a ROM for a variant. BUILDROM is the unified Symbian platform ROM building tool.
A variant configuration will be defined in .var file. Specify the VAR file name along with the FEATUREVARIANT keyword.
For example, if myvar.var is the VAR file name for variant myvar, then use:
buildrom [options] –DFEATUREVARIANT=myvar <obey1> [<obey2> ...]
Note: For more information on BUILDROM, refer to BUILDROM reference.