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Revision as of 17:10, 15 November 2012 by GNUtoo (talk | contribs) (TODO)
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The wiki is being retired!

Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to Contributions welcome!


Device/functionality Status Comments
CPU works OK Tested: AMD Athlon64 X2 250.
L1 cache enabled Untested Not tested yet
L2 cache enabled Untested Not tested yet
L3 cache enabled N/A
Multiple CPU support N/A
Multi-core support OK
Hardware virtualization OK KVM seem to work
DDR2 Untested
DDR3 OK 2G works, 4G(2 * 2G) works with lastest coreboot
Dual channel support Untested
ECC support Untested
On-board Hardware
On-board IDE 3.5" OK Tested: 500GB HDD
On-board IDE 2.5" N/A
On-board SATA OK Tested some ports, works fine
On-board SCSI N/A
On-board USB OK USB keyboard works
On-board VGA OK Tested:analog VGA and HDMI,dual screen.
On-board Ethernet OK
On-board Audio No Linux driver crashes.
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
On-board Wifi N/A
On-board Bluetooth N/A
On-board SD card reader N/A
Add-on slots/cards
ISA add-on cards N/A
Audio/Modem-Riser (AMR/CNR) cards N/A
PCI add-on cards OK I've an ath9k wifi PCI card and it works.
Mini-PCI add-on cards N/A
Mini-PCI-Express add-on cards Unknown
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 WIP a clean way to merge the patch must be found.
PCI Express x32 add-on cards Unknown
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, pins on board only
PS/2 keyboard OK
PS/2 mouse Untested
Game port N/A
Infrared N/A
PC speaker Untested
DiskOnChip N/A
Trackpoint N/A
Touchpad N/A
Fn Hotkeys N/A
Fingerprint Reader N/A
Docking VGA N/A
Docking LAN N/A
Docking USB N/A
Docking Audio N/A
Docking Displayport N/A
Thinklight N/A
Webcam N/A
Sensors / fan control Untested
Hardware watchdog N/A
SMBus Unknown
CAN bus N/A
CPU frequency scaling OK works in GNU/Linux
Other powersaving features Untested
ACPI Untested
Reboot OK
Poweroff OK
Suspend Unknown
Nonstandard LEDs
High precision event timers (HPET)
Random number generator (RNG) Untested
Wake on modem ring Untested
Wake on LAN
Wake on keyboard Untested
Wake on mouse Untested
TPM Unknown
Flashrom OK The chip is SPI


This pages is about the port to the M4A785T-M, this mainboard is very similar to the M4A785-M, but:

  • it has DDR3 instead of DDR2

The port is in the very early stages...(it will be ok when screen will not flickers at resolutions > 800x600)

Building the serial port adapter

You'll need to build a serial port adapter to get the coreboot logs during. Here's a picture of the serial port connector on the mainboard:
ASUS M4A785T-M serial connector witout serial adapter.jpeg
And here's the kind of cable you will need:
ASUS M4A785T-M serial connector with serial adapter.jpeg
And you'll need to build a cable similar to this one(on the picture the DB9 is connector is a male connector):
ASUS M4A785T-M serial cable.jpeg
Here's how it looks like on the mainboard:


Here's a table of corresponding pins:

Mainboard connector pin Mainboard pin Function Standard DE9 pin connector Standard DE9 pin Function Mandatory for coreboot
1 ? ? ? No
2 RX 3 TX Yes (you could do without but it's advised to get it, to be able to use certain functions of coreboot)
3 TX 2 RX Yes
4 4 DTR No
5 Ground 5 Ground Yes
6 ? ? ? No
7 7 RTS No
8 8 CTS No
9 ? ? ? No

Adapting GNU/Linux

Before booting with coreboot, do the following:

  • blacklist the snd-hda* modules (refer to the usual way to get help for the GNU/Linux distribution you want to run for doing that)
  • 32bit GNU/Linux trisquel distribution tested
  • 64bit GNU/Linux trisquel distribution failed to initialize the USB.

Building Coreboot

To build coreboot for this mainboard:

  • checkout coreboot revision 1b1309f289d6fc9f6ec348686665d25218535030
  • Configure and Build it as usual(for having graphics you need to extract your VGA BIOS ROM from your BIOS)



  • the -pae kernel didn't boot my LUKS hdd(failed at cryptsetup password entering)... => using a -generic kernel worked(however that sees only 2772M in htop(I've 4GB))
  • if you remove the PCIe card, the integrated ATI card won't come up...


From ab15ce791543cb0c1a09317962fe6bdc79e4e1b3 Mon Sep 17 00:00:00 2001
From: Denis 'GNUtoo' Carikli <>
Date: Tue, 18 Sep 2012 19:35:44 +0200
Subject: [PATCH] IRQ tables for getting the PCIe graphic card working

Thanks a lot for the help trough IRC in the #coreboot channel
  on the Freenode servers.

Change-Id: Ie99ee5adaf997cb94c96eb1942d1089ab2528f85
Signed-off-by: Denis 'GNUtoo' Carikli <>
 src/mainboard/asus/m4a785t-m/devicetree.cb |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/mainboard/asus/m4a785t-m/devicetree.cb b/src/mainboard/asus/m4a785t-m/devicetree.cb
index e8764b1..7095afd 100644
--- a/src/mainboard/asus/m4a785t-m/devicetree.cb
+++ b/src/mainboard/asus/m4a785t-m/devicetree.cb
@@ -10,8 +10,8 @@ chip northbridge/amd/amdfam10/root_complex
 			device pci 18.0 on #  northbridge
 				chip southbridge/amd/rs780
 					device pci 0.0 on end # HT  	0x9600
-					device pci 1.0 on end # Internal Graphics P2P bridge 0x9602
-					device pci 2.0 off end # PCIE P2P bridge (external graphics) 0x9603
+					device pci 1.0 off end # Internal Graphics P2P bridge 0x9602
+					device pci 2.0 on end # PCIE P2P bridge (external graphics) 0x9603
 					device pci 3.0 off end # PCIE P2P bridge	0x960b
 					device pci 4.0 off end # PCIE P2P bridge 0x9604
 					device pci 5.0 off end # PCIE P2P bridge 0x9605
@@ -24,7 +24,7 @@ chip northbridge/amd/amdfam10/root_complex
 					register "gpp_configuration" = "3"   # Configuration D default
 					register "port_enable" = "0x6fc"
 					register "gfx_dev2_dev3" = "1"
-					register "gfx_dual_slot" = "2"
+					register "gfx_dual_slot" = "0"
 					register "gfx_lane_reversal" = "0"
 					register "gfx_tmds" = "0"


  • Selecting the ASUS M4A77TD-PRO mainboard makes the serialICE shell appear once flashed(however running the BIOS under SerialICE fails at some point).


WARNING, This Howto is for SerialICE and not for coreboot, don't flash the resulting image unless you really know what you're doing...
git clone
cd serialice
make menuconfig


  • Add defaults for the nvram settings.
  • find a clean way to merge the patch for the PCIe graphic card.
  • fix the Audio CODEC(it's the same than the x60 and it works on the x60).
  • handle suspend to ram
  • lock SMM/SMI
  • make it possible to run the BIOS under serialICE
  • 64bit support