I made tests and the difference is notable. After 2.5.5, Phone (2) camera is much better in both HDR handling and detail retention.
Sadly, although the image quality was improved, there are still a couple of camera bugs that have been present for months. Basically the one where the image gets “hyper dramatic” colors when found closeups on indoor with artificial lightning, and the one where sometimes it takes a lot of time to have ready the picture thumbnail.
However, just talking about image quality, the improvement was pretty good.