Hex-core support on Sun X4600 M2

[clare]

I have a Sun X4600 M2, which officially supports Shanghain processors at HT1 speeds. I patched the BIOS by replacing the microcode with microcodes extracted from a Supermicro H8QME-2 BIOS and tried running it with a pair of hex-core 8431's. It booted, but the CPUs initialized as dual-core Opteron 8331's, and only a single CPU was detected. The BIOS also claimed that the CPU was stepping C1 (not D0 as they actually are).
It appears that the HT links to other CPUs are not initialized at all, in addition to the CPU being incorrectly detected.
Anyone know what's up? Obviously I missed some chunk in the BIOS that needs to be updated, but any idea what?