Not sure if it is the same issue but I had something similar where the battery meter would not increase when the battery was being charged. To solve it (and install the firmware), I had to run the surface until the battery was fully discharged then plug it in and let it charge for a while. After this the battery meter would fill back up and I could install updates; if I ever unplugged it, the same problem would occur and I'd have to do it over again.