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.