Marcello Sylvester Bauer eff1306ea4 Documentation/mb/lenovo: Test shrunken ME on Ivy Bridge

Update the Lenovo Ivy Bridge documentation that no issues could be
observed on W530.

Tested on Lenovo W530 with stripped ME and found no issues:
commit 93b0c7cfc6

* USB
* Bluetooth
* Wifi
* Wifi-kill switch
* libgfxinit
* SATA
* mSATA
* Audio
* SD-card
* Ethernet
* Keyboard
* Fn-Keys
* Display brightness
* ACPI S3 resume
* CPU temperature reporting
* Stress test stable (intel_pstate no_turbo due to W530 overheating bug)
  * Youtube videos
  * stress -c 8 -m 1 -t 3600

Change-Id: I46d23d41cc6ade5e641a6ddb3f357a6036002edc
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39603
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2020-03-31 10:32:25 +00:00

3.6 KiB

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Lenovo Ivy Bridge series

This information is valid for all supported models, except T430s and T431s.

Flashing coreboot

+---------------------+--------------------------------+
| Type                | Value                          |
+=====================+================================+
| Socketed flash      | no                             |
+---------------------+--------------------------------+
| Size                | 8 MiB + 4MiB                   |
+---------------------+--------------------------------+
| In circuit flashing | Yes                            |
+---------------------+--------------------------------+
| Package             | SOIC-8                         |
+---------------------+--------------------------------+
| Write protection    | No                             |
+---------------------+--------------------------------+
| Dual BIOS feature   | No                             |
+---------------------+--------------------------------+
| Internal flashing   | Yes                            |
+---------------------+--------------------------------+

Installation instructions

Update the EC firmware, as there's no support for EC updates in coreboot.
Do NOT accidently swap pins or power on the board while a SPI flasher is connected. It will permanently brick your device.
It's recommended to only flash the BIOS region. In that case you don't need to extract blobs from vendor firmware. If you want to flash the whole chip, you need blobs when building coreboot.
The Flash layout shows that by default 7MiB of space are available for the use with coreboot.
In that case you only want to use a part of the BIOS region that must not exceed 4MiB in size, which means CONFIG_CBFS_SIZE must be smaller than 4MiB.
ROM chip size should be set to 12MiB.

Please also have a look at :doc:`../../flash_tutorial/index`.

Splitting the coreboot.rom

To split the coreboot.rom into two images (one for the 8MiB and one for the 4 MiB flash IC), run the following commands:

dd of=top.rom bs=1M if=build/coreboot.rom skip=8
dd of=bottom.rom bs=1M if=build/coreboot.rom count=8

That gives one ROM for each flash IC, where top.rom is the upper part of the flash image, that resides on the 4 MiB flash and bottom.rom is the lower part of the flash image, that resides on the 8 MiB flash.

Dumping a full ROM

If you flash externally you need to read both flash chips to get two images (one for the 8MiB and one for the 4 MiB flash IC), and then run the following command to concatenate the files:

cat bottom.rom top.rom > firmware.rom

Flash layout

There's one 8MiB and one 4 MiB flash which contains IFD, GBE, ME and BIOS region. These two flash ICs appear as a single 12MiB when flashing internally. On Lenovo's UEFI the EC firmware update is placed at the start of the BIOS region. The update is then written into the EC once.

Reducing Intel Managment Engine firmware size

It is possible to reduce the Intel ME firmware size to free additional space for the bios region. This is usually referred to as cleaning the ME or stripping the ME. After reducing the Intel ME firmware size you must modify the original IFD, split the resulting coreboot ROM and then write each ROM using an external programmer. Have a look at me_cleaner for more information.

Tests on Lenovo W530 showed no issues with a stripped and shrunken ME firmware.

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