ちなみに(どうでもいい情報かもしれませんが・・・)
アップデートしたBIOSの各変更点は下記のようです。

| 1. Support M520/M530 CPU, but without C3 mode support
| 1. Fixed WHQL fail with SMBIOS.
| 1. Update VGA BIOS from 008.050I.038.000 (BR24398.TST) to 008.050I.075.000 (BR25725.TST)
| 1. Fix crisis function fail issue.
| 2. Support Win XP SLP by update DMI SYSTEM Manufacturer string.
| 1. Enable hardware base DEP function.
| 2. Support MX29LV008CTTC flash ROM.
| 1. Update MCU to support T5500 CPU(06F2h)
| 2. Support boot from LAN by setting CMOS 06Ch/bit0

以上、ありがとうございました。