Intel Sandybridge Build Tutorial

Step by Step Tutorial How to flash coreboot onto Lenovo T520. Flashing coreboot on supported Intel SandyBridge / Ivybridge system is very similar to this one. Steps that need to be changed are marked as those.

Chapters:

• Check the board status
• Setup toolchain
• Get binary blobs
• Configure coreboot
• Build coreboot
• Flash coreboot
• Recovery and Debugging

For more information have a look at Build_HOWTO

Get binary blobs

Coreboot needs some binary blobs. Here's a list of blobs required: Binary_situation

I'm going to use:

• Intel Management Engine (ME)
• Intel Flash descriptor (IFD)
• Intel Gigabit Engine (GBE)

You may want to extract the VGA Option Rom, too: VGA_support

Warning: Remove all batteries and unplug the power connector. You have to make sure to supply enough current through the programmer.

The Beaglebone Black onboard voltage regulator doesn't supply enough current. Using an external power supply may be required.

Some flash chips can't be programmed while soldered, as the southbridge is powered, too, and communicates with the flash.

The T520 flash IC can be programmed in circuit.

I used the TIAO USB board to access the flash. You need a flashrom version supporting the "tumpa" programmer. Of course you can read the flash using the Raspberry or BeagleBone, too. To read the flash chip using tumpa programmer:

flashrom -p ft2232_spi:type=tumpa,port=A,divisor=4 -r T520.bin

To read the flash chip using raspberry pi:

flashrom -p linux_spi:dev=/dev/spidev0.0 -r T520.bin

Extract the binary blobs from the raw flash image:

cd ./util/ifdtool
make
./ifdtool -x T520.bin

The following files will show up:

• flashregion_0_flashdescriptor.bin
• flashregion_1_bios.bin
• flashregion_2_intel_me.bin
• flashregion_3_gbe.bin

Configure Coreboot

Run:

make menuconfig

In menu General Setup:

Set "Set CMOS for configuration values"

In menu Mainboard:

Set "Mainboard Vendor" to "Lenovo"
Set "Mainboard model" to "T520"

For other boards choose your settings here !

In menu Chipset:

Set "Add Intel descriptor.bin file" to "flashregion_0_flashdescriptor.bin"
Set "Add Intel ME firmware" to "flashregion_2_intel_me.bin"
Set "Add Gigabite Ethernet firmware" to "flashregion_3_gbe.bin"

In menu Devices:

Set "Use native graphics initialization"

Warning: "native graphics initialization" is only supported on Intel mobile GPUs using LVDS and remove the need to run the Option Rom to get graphics output.

In case you want to run VGA Option Rom add it using:

Set "Add a VGA BIOS image" to the VGA Option ROM file

In menu Payloads:

Set "Include generated option rom that implements legacy VGA BIOS"

Save the new config

Run:

make

Flashing coreboot

Recommended

1. Extract the flash layout using ifdtool

./util/ifdtool/ifdtool -f T520.layout T520.bin

It creates a file looking like that:

00000000:00000fff fd
00500000:007fffff bios
00003000:004fffff me
00001000:00002fff gbe
00fff000:00000fff pd
00fff000:00ffffff res1
00fff000:00ffffff res2
00fff000:00ffffff res3
00000000:00ffffff ec

2. Remove "disabled" regions: Remove all regions that are disabled or invalid as flashrom can't ignore them, here:

pd, res1, res2, res3, ec

The new file will look like this:

00000000:00000fff fd
00500000:007fffff bios
00003000:004fffff me
00001000:00002fff gbe

3. Connect an external programmer to your flash IC and run the flashrom command to override only the BIOS flash region, leaving IFD, ME, and GBE where it is.

flashrom -p ft2232_spi:type=tumpa,port=A,divisor=4 -l ./T520.layout -i bios -w ./build/coreboot.rom

Overwriting the whole flash

In case you bricked something or you want to replace the ME blob you have to write the whole flash IC. In this case there's no need for a layout file. The command to write the coreboot image is:

 flashrom -p ft2232_spi:type=tumpa,port=A,divisor=4 -w ./build/coreboot.rom

Warning: Sandybridge Chipsets need a matching ME blob and IFD ! The board won't boot at all if one of them is invalid.

Recovery and Debugging

TODO