This page describes how to run coreboot on the ASUS P3B-F mainboard.

Flashing coreboot

Type Value
Model SST 39SF020A (or similar)
Protocol Parallel
Size 256 KiB
Package DIP-32
Socketed yes
Write protection See below
Internal flashing yes

flashrom supports this mainboard since commit c7e9a6e15153684672bbadd1fc6baed8247ba0f6. If you are using older versions of flashrom, below has to be done (with ACPI disabled!) before flashrom can detect the flash chip:

  #  rmmod w83781d
  #  modprobe i2c-dev
  #  i2cset 0 0x48 0x80 0x80

Upon power up, flash chip is inaccessible until flashrom has been run once. Since flashrom does not support reversing board enabling steps, once it detects the flash chip, there will be no write protection until the next power cycle.

CPU microcode considerations

By default, this board includes microcode updates for 5 families of Intel CPUs because of the wide variety of CPUs the board supports, directly or with an adapter. These take up a third of the total flash space leaving only 20kB free in the final cbfs image. It may be necessary to build a custom microcode update file by manually concatenating files in 3rdparty/intel-microcode/intel-ucode for only CPU models that the board will actually be run with.


  • Slot 1 and Socket 370 CPUs and their L1/L2 caches
  • PS/2 keyboard with SeaBIOS (See [Known issues])
  • IDE hard drives
  • USB
  • PCI add-on cards
  • AGP graphics cards
  • Serial ports 1 and 2
  • Reboot

Known issues

  • PS/2 keyboard may not be usable until Linux has completely booted. With SeaBIOS as payload, setting keyboard initialization timeout to 2500ms may help.
  • The coreboot+SeaBIOS combination boots so quickly some IDE hard drives are not yet ready by the time SeaBIOS attempts to boot from them.
  • i440BX does not support 256Mbit RAM modules. If installed, coreboot will attempt to initialize them at half their capacity anyway whereas vendor firmware will not boot at all.
  • ECC memory can be used, but ECC support is still pending.


  • Floppy
  • Parallel port
  • EDO memory
  • ECC memory
  • Infrared
  • PC speaker

Not working


Northbridge Intel I440BX
Southbridge i82371eb
CPU P6 family for Slot 1 and Socket 370 (all models from model_63x to model_6bx)
Super I/O winbond/w83977tf

Extra resources