a quick easy change would be to alter the cold/warm/hot injection ratio tables for port/direct injection ratio.
zero out the values up to 0.3 engine load. this usually helps idle stability.
Theory is with direct injection only fueling adjustment is quicker (direct to cylinder rather than injected into intake port runner) and your not asking the port injectors to inject very small amounts of fuel at idle where they are likely non-linear
but during initial startup i believe ECU uses port injection only so your probably going to have to adjust the idle stability A/B tables as per previous post as well.
