Removing the back cover at this final step was had for me; I had to use a flathead screwdriver to separate the back edge of the cover away…I was not able to separate the lower case all the way by pulling the lower case up and toward me as shown in the photo.
I did this procedure twice on 9 June 2019; to remove a working DC-In Card from a “hanger queen” 12”iBook, and install it into an operational G4 iBook with a bad DC-In Card. I lack mechanical expertise as well as strength in my hands, but wanted to try doing this because having someone else fix my iBook would cost 3 or 4 times as much as the iBook is currently worth! Anyway, after researching the take-apart steps here and on YouTube, I first bought a toolset and spudgers from my local Micro Center before attempting the DC-In Card removal and replacement. My “hangar queen” iBook was easier to take apart since it had been worked on previously before being declared “dead.” I really had trouble separating the back cover from the working iBook because it had not been opened for a very long time. I kept at it, and was finally able to separate the back cover, remove the metal interior cover, install the “good” DC-in Card back into my working iBook, and put it back together. My iBook is now charging as it should.