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Revision as of 23:38, 3 May 2012 by GNUtoo (talk | contribs) (→‎Pictures: Add new pictures with resistor)
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This page is a first draft only and serves to collect information about the serprog protocol and the programmers implementing it.


See serprog-protocol.txt in the source tree. It is designed to be compact and allow efficient storage in limited memory of programmer devices.

There is a draft for an extension of the serprog protocol to SPI. FIXME: Link there.

Note that beside the really mandatory serprog commands, if you also implement the O_SPIOP command correctly, it should be enough for flashrom from svn to work correctly.


AVR flasher by Urja Rannikko

Prototype RS232 AVR parallel flash programmer

The Prototype RS232 AVR parallel flash programmer Urja Rannikko was the first implementation of the serprog protocol.

FIXME: AVR source code is somewhere in the coreboot mailing list archives...

AVR flasher by eightdot

FIXME: Link?

Arduino Mega flasher by fritz

[1] [2] FIXME: More info?

Arduino Uno flasher by GNUtoo

This flasher require the following hardware parts:

  • An arduino uno and its usb cable
  • some wires(optionally some connectors to solder on(for easier plugin and more reliability)
  • a 10k resistor
  • a flash chip to flash


Serprog 0001.jpeg Serprog 0002.jpeg Serprog 0003.jpeg Serprog 0004.jpeg Serprog 0005.jpeg Serprog 0006.jpeg


Left pins of the BIOS chip:
[pin1 of the bios chip] /CS<->10k resistor<->VCC 

[pin1 of the bios chip] /CS<->Arduino pin10(SS, PORTB2)
[pin2 of the bios chip] DO<->Arduino pin12(MISO, PORTB4)
[pin3 of the bios chip] /WP<->VCC
[pin4 of the bios chip] GND<->GND on the power pins

Right pins of the BIOS chip:
[pin8 of the bios chip] VCC<->+3.3V on the power pins of the Arduino
[pin7 of the bios chip] /HOLD<->VCC
[pin6 of the bios chip] CLK<->Arduino pin13(SCK, PORTB5)
[pin5 of the bios chip] DIO<->Arduino pin11(MOSI, PORTB3)

The Bios chip used is a W25X80. 
The Arduino is an arduino uno.



# time flashrom -p serprog:dev=/dev/ttyACM0:115200 -r coreboot.rom 
flashrom v0.9.5.2-r1523 on Linux 3.0.0-17-generic-pae (i686), built with libpci 3.1.7, GCC 4.5.2, little endian
flashrom is free software, get the source code at

Calibrating delay loop... OK.
serprog: Programmer name is "serprog-duino"
Found Winbond flash chip "W25X80" (1024 kB, SPI) on serprog.
Reading flash... done.

real	1m40.680s
user	0m0.884s
sys	0m0.268s

Required software

To make it work you need:

Building the software

$ svn co svn:// flashrom
$ cd flashrom && make
$ cd ../
$ git clone git://
$ cd serprog-duino && make && make upload

Running flashrom

./flashrom -p serprog:dev=/dev/ttyACM0:115200

Advantages and disadvantages

  • While the speed isn't that great(less than 10 minutes for reading+writing+verifying a 1M chip), there is huge room for improvements in the source code.
  • it is made of very commonly available parts(if you can find an arduino uno, you will be able to build it).

InSystemFlasher by Juhana Helovuo

This is one uses a modified serprog version to talk to SPI devices via serial over USB. Details can be found in the coreboot wiki and in this coreboot mailing list thread.

atmegaXXu2-flasher by Stefan Tauner

Like the InSystemFlasher this one uses LUFA on an AVR microcontroller to tunnel the serial data over USB. To be updated when flashrom's serprog module has the needed changes merged to do SPI communication.

atmegaXXu2-flasher with Pomona SOIC hook attached