HP A7818-IE002 - Manual (Page 92)

Tests And Error Messages
Order In Which POSTs Occur
Chapter 4 92
a. If the BIOS detects error 2C, 2E, or 30 (base 512KB RAM error), it displays an
additional word-bitmap (xxxx) indicating the address line or bits that failed. For
example:
2C 0002 means line 1 (bit one set) has failed.
2E 1020 means data bits 12 and 5 (bits 12 and 5 set) have failed in the lower 16
bits.
The BIOS also sends the bitmap to the port-80 LED display. It first displays the
checkpoint code, followed by a delay, the high-order byte, another delay, then the
low-order byte of the error. It repeats this sequence continuously.