Tag: Rasberry Pi

Flashing a BIOS chip with a Raspberry Pi

I made this post as a addition or supplement to my “Flashing a BIOS chip with an Arduino” post.

While doing some research online I found several articles/posts from people using a Raspberry Pi to flash SPI flash chips. Apparently the Raspberry Pi  is very suitable for this kind of thing as it has a SPI interface and is able to run linux. I was eager to try this out for myself so I got out my Pi 3 model B and got to work. For this project I used a Winbond 25X80 salvaged from a motherboard I had lying around.

Preparing the RaspberryPi

As others have pointed out, the latest version of Raspbian (Stretch) will also work by adding the spispeed param to the Flashrom command.

Enable the SPI interfaces by typing sudo raspi-config and selecting P4 SPI under the Interfacing options.

Select option 5: Interfacing options
Select SPI to enable the SPI interfaces

The SPI interfaces will become available under /dev/spidev0.0 and /dev/spidev0.1.

Next we install the packages are needed by Flashrom by using the following command.

sudo apt install git libpci-dev libusb-1.0 libusb-dev

Make and install Flashrom.

git clone https://github.com/flashrom/flashrom.git
cd flashrom
make && sudo make install

 

Connecting the Raspberry to the SPI flash chip

The table below show the connections between the RaspberryPi and the chip.

RPi pin SPI flash
25 GND
24 CS
23 SCK
21 DO
19 DI
17 VCC 3.3V and /HOLD and /WP

Flashing the chip

In order to verify Flashrom correctly identifies the chip we run Flashrom without any operations.

pi@raspberrypi:~ $ flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=512
flashrom p1.0-76-g291764a on Linux 4.14.34-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Winbond flash chip "W25X80" (1024 kB, SPI) on linux_spi.
No operations were specified.

Now that Flashrom correctly identifies the Winbond W25X80 we can continue to backup the current BIOS.

pi@raspberrypi:~ $ flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=512 -r flash.dat
flashrom p1.0-76-g291764a on Linux 4.14.34-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Winbond flash chip "W25X80" (1024 kB, SPI) on linux_spi.
Reading flash... done.

After backing up the old BIOS we can safely write the new BIOS back to the chip.

pi@raspberrypi:~ $ flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=512 -w flash.dat 
flashrom p1.0-76-g291764a on Linux 4.14.34-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Winbond flash chip "W25X80" (1024 kB, SPI) on linux_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... 
Warning: Chip content is identical to the requested image.
Erase/write done.

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