There’s a manufacturer-supplied video in our Ankhmaway technical information that shows how to open the iB004N. We haven’t been happy with this video for some time. Firstly, if you open the beacon as shown you are likely to crack the case. Secondly, it shows someone wielding what looks like a metal screwdriver that, given where it’s used, could easily short or damage the circuit board. Thirdly, if you snap it shut as shown, you will snap off the retaining lugs.
We have found that the best way to open the iB004N is with a plastic sharp edge such as a guitar pick. Push it down as shown, where there isn’t a retaining lug:
Lever and the case top pops off. Use a plastic tool to lever up the printed circuit board and replace the battery.
To put the lid back on, first place the lid side with the two lugs into the corresponding two holes in the side. Push the lid down and use the plastic sharp edge, in the same position as you used to take the lid off, to widen the case slightly as you push the lid right down. This way, the lug won’t snap off.