Why don't you use GrCreateContext?
e.g.
/* GrSetDriver("memory gw 640 gh 400 nc 256"); */ GrSetMode(GR_default_graphics); GrContext* mem1 = GrCreateContext(640,400,NULL,NULL); GrContext* mem2 = GrCreateContext(640,400,NULL,NULL);
GrSetContext(mem1); ... GrSetContext(mem2); ...
GrDestroyContext(mem1); GrDestroyContext(mem2);
Maybe GrCreateFrameContext(GR_FrameRAM8,640,400,NULL,NULL); will do it without even switching to graphics-mode. You try and report!
Marcus