The following is the Unity test output:

OpenGL vendor string:   NVIDIA Corporation
OpenGL renderer string: GeForce FX 5500/AGP/SSE2
OpenGL version string:  2.1.2 NVIDIA 173.14.30

Not software rendered:    yes
Not blacklisted:          no
GLX fbconfig:             yes
GLX texture from pixmap:  yes
GL npot or rect textures: yes
GL vertex program:        yes
GL fragment program:      yes
GL vertex buffer object:  yes
GL framebuffer object:    yes
GL version is 1.4+:       yes

Unity supported:          no

As you can see, all requirements are fulfilled but my GPU is blacklisted. What can I do about it?