Michael Mecham posted on Aviation Week's Things with Wings blogs a comment attributed to Boeing Chairman and CEO McNerney that the fixes "were installed" in "10 fleet aircraft and 9 production aircraft". That sounds like "all done".
Mecham battery progress post
However, a Boeing VP posting in his own voice on his own blog, VP Marketing for Boeing Commercial Airplanes, describes it as "We’ve started installation on 10 787s already in the customer fleet, as well as nine production airplanes. The bulk of the fleet retrofits should be wrapped up by mid-May. 787 deliveries are expected to resume in early May."
Tinseth blog (look for the second paragraph of the entry which first mentions the quarterly earnings report. It is the top entry at the moment I am posting, but will move down).
I don't usually expect the Marketing channel to have the more accurate story, but in this case my bet is on Randy, not on McNerney as quoted by Mecham. Boeing has elsewhere described the installation as taking about 5 elapsed days on an airframe, and I think they did not start customer fixes nor most in-process birds until the approval came through. I'm talking about bending and cutting metal and composite--not about pre-positioning people and materials, which clearly happened. Randy comments in his post that he was in Ethiopia at the time of writing. I'd guess that may hint that the widespread story that Ethiopian may be the first airline flying seems more likely than some may have thought.