How to open my router
From DD-WRT Wiki
 How To Open the Buffalo WHR-HP-G54 Router
1. Remove antenna, desktop stand, etc.
2. Using a sharp knife, carefully scribe through the label along the seam between the two case halves, as shown in Figure 1.
3. Using a pair of pointed tweezers, or like instruments, carefully push through the label and into the two holes as shown in Figure 2.
4. Using the tweezers, push straight down and then forward to push the plastic bezel away from the router, as seen in figure 3.
5. Pull the bezel away from the router, disengaging the bezel tab from the AOSS Button on the other end of the router. Set Bezel aside.
6. Note that one of the gray side panels has a thumb notch to aid in removal. Push down and in the direction of the arrow in Figure 4. The panel will slide free of the router. Set it aside.
7. Once the panel is removed, you will see a T-9 Torx head screw. Using a T-9 Torx bit or driver, remove this screw and set it aside. See Figure 5.
8. Set the router on edge, with the AOSS button facing up. Carefully start separating the 2 case halves. As the halves come apart, lift up on the blue plastic strip that includes the AOSS button. When the halves are approximately ¼ inch apart, the plastic strip and AOSS button will lift away from the router. Set the strip aside. See Figure 6.
9. Carefully lay the router on its side, with the side that you removed the panel from facing down. Lift the top half of the router away from the bottom half. As you do this, you will see the clear, plastic LED manifold come into view. Carefully lift it up and away from the router. See Figures 7 and 8.
10. Continue lifting the front of the top case half as it pivots on the hinges that secure the back of the case halves together. When the top case half is nearly perpendicular to the bottom half, it will separate from the hinges and pull away. It may take a bit of wiggling to separate the hinges, but it shouldn't take a great deal of force. See figure 9.
11. The board will lift out of the bottom case half at this point.
Reassemble in reverse order. Good luck!!