Problem on R415 with Opteron 4200 series

hi team.

i have problem on R415. current, i use opteron 4162EE with bios 2.2.1 (latest for now).
And today, i change cpu to 4284. The server can boot normally until come to step before enter windows 2008r2 OS.

i saw the screen showing by "Error: Unsupported CPU and motherboard combination. please install opteron 4100 series cpu." and cannot goto any where.

Somebody can help me know how to fix them?

thank
foxley