ASUS M4A78-EM

This HOWTO explains how to use coreboot on the ASUS M4A78-EM board.

Status

Device/functionality	Status	Comments
CPU
CPU works	OK	Tested: AMD Sempron 140.
L1 cache enabled	OK	-
L2 cache enabled	OK	-
L3 cache enabled	N/A
Multiple CPU support	N/A
Multi-core support	Untested
Hardware virtualization	Untested	-
RAM
EDO	N/A
SDRAM	N/A
SO-DIMM	N/A
DDR	N/A	N/A
DDR2	OK	1G tested
DDR3	N/A
Dual channel support	Untested
ECC support	Untested
On-board Hardware
On-board IDE 3.5"	OK	Tested: CD/DVD-RW
On-board IDE 2.5"	N/A
On-board SATA	OK	Tested: SATA port 1.
On-board SCSI	Unknown
On-board USB	OK	Mouse attached crashes SeaBIOS
On-board VGA	OK	Tested: DVI and analog VGA. Untested: HDMI.
On-board ethernet	OK
On-board audio	Untested	-
On-board modem	N/A
On-board FireWire	N/A
On-board smartcard reader	N/A
On-board CompactFlash	N/A
On-board PCMCIA	N/A
Add-on slots/cards
ISA add-on cards	N/A
Audio/Modem-Riser (AMR/CNR) cards	N/A
PCI add-on cards	Untested	-
Mini-PCI add-on cards	N/A
PCI-X add-on cards	N/A
AGP graphics cards	N/A
PCI Express x1 add-on cards	Untested
PCI Express x2 add-on cards	N/A
PCI Express x4 add-on cards	N/A
PCI Express x8 add-on cards	N/A
PCI Express x16 add-on cards	Untested
PCI Express x32 add-on cards	N/A
HTX add-on cards	N/A
Legacy / Super I/O
Floppy	N/A	There is no floppy connector at all.
Serial port 1 (COM1)	OK	COM1 is only pin header on board. DB-9 serial connector is available, but not included with board.
Serial port 2 (COM2)	N/A
Parallel port	Untested	No connector, pin header on board only.
PS/2 keyboard	OK
PS/2 mouse	N/A
Game port	N/A
Infrared	N/A
PC speaker	Untested
DiskOnChip	N/A
Miscellaneous
Sensors / fan control	OK	Single temperature reported.
Hardware watchdog	Untested
SMBus	Unknown
CAN bus	N/A
CPU frequency scaling	OK	Powernow-K8 works.
Other powersaving features	Untested
ACPI	Untested	-
Reboot	No
Poweroff	No
Suspend	Unknown
Nonstandard LEDs	N/A
High precision event timers (HPET)	No	Linux detects, but disables HPET.
Random number generator (RNG)	Untested
Wake on modem ring	Untested
Wake on LAN
Wake on keyboard	Untested
Wake on mouse	Untested
Flashrom	OK

Building coreboot

See the Build HOWTO for general information on how to build coreboot.

This board is very similar to ASUS M4A785-M. The major differences are

• Chipset is AMD 780G and SB700 (instead of 785G and SB710).
• On-board VGA is ATI Radeon HD3200 (instead of HD4200), PCI id 1002:9610 (instead of 1002:9710), and
• One of the six SATA ports is eSATA.

There is now (tested on revision 6151) support for M4A78-EM in Coreboot.

Get the Coreboot sources and build tools. Download or build a SeaBIOS binary.

VGA BIOS for the onboard ATI Radeon can be extracted from the original BIOS with the bios_extract utility.

Invoke menuconfig.

• Select Mainboard to be Asus M4A78-EM, ROM chip size 1 MB.
• From "Console options" select "Use onboard VGA as primary video device" if you use the onboard ATI Radeon.
• Add the extracted VGA BIOS, set PCI ids to 1002,9610.
• Add SeaBIOS payload.

Compile with make and flash.

ROM Chip

Up-to-date Flashrom should be able to detect, read, and write the BIOS ROM. The chip is 8 Mbit cFeon EN25F80. It is in DIP-8 package and installed in a socket, so it can be changed without soldering. The ROM is accessed via the SPI protocol. I also tested a Macronix MX25L8005 chip as a substitute, and it worked fine.

Known issues

RAM

• 1 GB RAM (1 x Kingston KVR800D2N5/1G) - Boots

Payloads

• SeaBIOS version 0.6.1 works
  • Can boot Debian Linux from SATA drive via Grub2.
• Coreinfo works.
  • Both as standalone payload or loaded from SeaBIOS
  • Both serial port and VGA+PS2 keyboard work.
• FILO works ok.