AgsiSetWatchOnMemory in C166 can't work properly

my code like this:

end=g_FlashMemBase+g_flashMemSize-1;
tmp.Format("MAP 0x%x ,0x%x READ WRITE EXEC",g_ FlashMemBase,end);
Agsi.ExecuteCommand(tmp);
ret &=Agsi.SetWatchOnMemory(g_FlashMemBase, end,FlashRead,AGSIREAD);

FlashRead can only catch memory read when g_flashMemSize<=4.