Be sure to disconnect all the ribbon cables from the mainboard before lifting it out.

I also had to remove the metal cover on the upper left-hand side of the mainboard (directly under the camera) in order to safely remove the battery cable; it’s also helpful to disengage the camera lock (see “camera replacement” guide) and remove the camera+battery cable guide to make it easier to fiddle the cable out of the housing.

as shown in the picture, the kickstand must be closed all the way in order to extract the locking mechanism far enough to remove the battery!