This is a new problem that recently manifested with the latest update. I cannot use the power button to turn the 3DS on unless I plug in the adapter. And when the adapter cord is unplugged from the unit it immediately shuts off. At first I thought it was most likely the battery, but after swapping the battery with another system, the problem persists. (The other system has no issue starting without the adapter with the swapped battery.)
I have also tried a soft reset to no avail.
The other strange thing that I have noticed is that the Icons are taking a very long time to load when the system starts (3-5 seconds). This is also a new problem that just started.
I have read already that others who are having a similar problem with the power button have tried factory resets with no luck solving the issue, which makes it seem like it's not a hardware issue at all but a software problem.
Technical Support help would be quite welcome with this issue. I do not wish to reformat if it can be avoided.