Using less space on my iphone for android?

I dual booted my iphone with android i was just wondering is their a way to make ios use less space for android so like make android my main os for my iphone 4 i don't like ios i'm not going to use it at all

If you don't like iOS but have an iPhone, why not just get an Android phone? But if you insist, you'll have to keep iOS on it as Apple locks their devices down.