Кроме User Guide есть Technical Product

Почему-то нашел на Интеле только юзер гид, где упоминаются эти светляки, но нетописания их значений.
... не указано, в каком порядке считать светляки

9.8 Diagnostic LEDs
All port 80 codes are displayed using the Diagnostic LEDs found on the back edge of the baseboard. The diagnostic LED feature consists of a hardware decoder and four dual color LEDs. During POST, the LEDs will display all normal POST codes representing the progress of the BIOS POST.

Each code will be represented by a combination of colors from the four LEDs.
The LEDs are capable of displaying three colors: Green, Red, and Amber. The POST codes are divided into two nibbles, an upper nibble and a lower nibble. Each bit in the upper nibble is represented by a Red LED and each bit in the lower nibble is represented by a green LED. If both bits are set in the upper and lower nibbles then both Red and Green LEDs are lit, resulting in an Amber color. If both bits are clear, then the LED is off.
In the below example, BIOS sends a value of ACh to the Diagnostic LED decoder. The LEDs are decoded as follows:
Red bits = 1010b = Ah
Green bits = 1100b = Ch
Since the red bits correspond to the upper nibble and the green bits correspond to the lower nibble, the two are concatenated to be ACh.