What I've done to to the replace the D1692 Phoenix BIOS with the Tyan S2885 AMI BIOS was following:
I used Uniflash and hotflashed the AMI BIOS, including bootblock, onto a new chip.
So You have still the old BIOS version on the old chip.
A trick for easy PLCC extraction is to take a pinboard pin, cut off the steel needle, and superglue the plastic handle onto the PLCC chip.
Regarding onboard GBit NIC:
I have finally found out, how to enable the onboard Boadcom BCM5703C Gigabit LAN on the D1692 OEM S2885 boards.
You only need an exacto knife
As suspected, the main difference between a real S2885 and the Fujitsu Siemens OEM D1692 is the BIOS enabling/disabling a GPIO pin of the W83627HF chip.
The Fujitsu Siemens Phoenix BIOS enables it, while the Tyan AMI one disables the pin.
This post http://www.0x61.com/forum/post5604466.html
identified pin 72.
So I traced my board and pin 72http://img199.imageshack.us/img199/2200/w83627hfpin72via.jpg
is connected on the topside with pin 5 ( /WP Write Protect) of the AT45DB11 serial flash, next to the AGP slot,http://img853.imageshack.us/img853/5464/bcm5703ctop.jpg
and on the underside of the board to a voltage divider made of SMD resistors R1094 (1K), R1093 (1K pull up to 2.5V) and R1092 (4.7K), located between BCM5703 and the AGP slot, and trough it with pin 4 ( /CS Chip Select) of the flash and a pad of the BCM5703C.http://img534.imageshack.us/img534/3681/bcm5703cbottom.jpg
See the schematichttp://img824.imageshack.us/img824/7346/d1692.gif
To get the BCM5703C working, it's ATMEL flash must have enabled writes i.e. it's pin 5 must be high.
Therefore I cut the trace between GPIO pin 72 and pin 5 of the flash.
The above mentioned resistors provied the nessesary voltage level pullup.
I've chosen the trace cut by it's via next to pin A6 of PCI slot 5 underside. http://img846.imageshack.us/img846/7266/pcislot5.jpg
Now the NIC is recognised in the bios and works.
My two Dual-Core Egypt Opterons 280HE work now.
The only remaining problem is heat, at least the ADT7463 temperature sensor "Local" , next to CPU1 VRM on the back ATX PS2 connections, must be below 44°C
, else there is automatic power o
Temp1 (front) und Temp2 (center board) of the W83627HF must be below 40°C.
Sensor values read with Speedfan.
Have glued 2 heatsinks on the VRM power MOSFET's as in theTyan Board Manual PDF picture.
Advisable is automatic Powernow undervolting/multiplicator underclocking with CrystalCPUID.