Trouble with Boss

I've been having trouble with my boss at work and we have developed poor rapport. I'm looking for advice on rectifying this relationship. Truly, anything that might help would be of value (and I know what I'm opening myself up to on this forum when I say that). 

Here's the deal: I work in a quatamental equity research team. This team is noted for its high performers and expects the best out of its members. It's divided into two units, and the leader of the unit I am in is my boss. 

Unfortunately, my boss and I have developed a poor relationship. When I began working for him a few months ago, we were fairly harmonious. But after a negative reaction by a well-respected senior research analyst to the first project I worked on, our formerly good rapport has soured. After delivering this project, I took a few days off for the CFA exam. When I returned post-exam, something was "off" as if something had happened. Despite this, he assigned me a few other projects to work on. We maintained a working relationship up to this point and regularly communicated about the work. But only after about ~3 weeks on these projects, he told me to stop working on them completely. 

His boss has since stepped in and been working with me on my current project. The work is impactful and the rapport I have built with my boss' boss is good. However, my boss' boss will be leaving the company in about a month, and my current boss will be taking his position. After my boss' boss leaves, I will continue to report to my current boss in my current capacity, and he will oversee the other unit of the team in addition to my unit. Consider it a promotion for him. 

Seeing that these things will happen and that I need to continue my current work (and hopefully get some new work), I need to rebuild better rapport with my current boss. We currently interact at a minimum and act cordially when in meetings, but rarely talk about the work we each are doing. In fact, we barely talk outside of those group meetings at all. He does not assign me any work either. 

Lastly, my boss' boss asked my boss for feedback on my current work and I was able to speak with my boss' boss about how I've been doing in the job. The feedback I received was tough and honest, and I've worked to incorporate changes in my work to be of greater value to the team. My boss' boss believes that there has been noticeable improvement in my work since having this feedback conversation and is encouraged about my future with the company.

What can I do to rekindle my relationship with my boss? Since the person I work with most closely now will be leaving, I believe that for the remainder of the time I am in this job, I should try to establish goodwill with my boss. I want to have at least one successful project with him and reverse the negative sentiment being spread about me concerning my performance both within in the company and across the industry. 

Other than leaving the company or changing to a different group, what is the best course of action? For various reasons (mainly personal), I probably will be staying with this company in the short-term but am open to leaving. I have already applied for different groups internally, but the soonest I can expect to move to a new area is July. Additionally, moving internally will be much easier if I can turn my relationship around with my current boss. 

Thank you for reading this long post. I'm open to any feedback here. I really do want to turn this around and have a good relationship with my boss. Let me know if there is anything I can do.