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Documentation/mainboard/facebook/monolith.md: Add flash components

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Add description of the procedure to create the flash components for this
system.

BUG=N/A
TEST=N/A

Change-Id: I2690dfbe715fa120f840d98c57fdc3fd7e8b45b1
Signed-off-by: Wim Vervoorn <wvervoorn@eltan.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38588
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
This commit is contained in:
Wim Vervoorn
2020-01-24 15:37:39 +01:00
committed by Patrick Georgi
parent 272fecafbb
commit c4a71467d1
1 changed files with 38 additions and 0 deletions
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Documentation/mainboard/facebook/monolith.md
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@@ -13,12 +13,50 @@ fsp blobs 3rdparty/fsp/KabylakeFspBinPkg/Fsp_M.fd
Microcode 3rdparty/intel-microcode/intel-ucode
## Flash components
To create a complete flash image, the flash descriptor, GBE and ME blobs are required. The
complete image can be used when e.g. a blank flash should be programmed. In other cases (when
only coreboot needs to be replaced) placeholders can be used for the GBE and ME regions.
These can be extracted from the original flash image as follows:
1) Read the complete image from flash.
2) Create a layout file with the following content:
```
00000000:00000fff fd
00700000:00ffffff bios
00003000:006FFFFF me
00001000:00002fff gbe
```
3) Use `ifdtool -n <layout_file> <flash_image>` to resize the *bios* region from the default 6MB
to 9 MB, this is required to create sufficient space for LinuxBoot.
NOTE: Please make sure only the firmware descriptor (*fd*) region is changed. Older versions
of the ifdtool corrupt the *me* region.
4) Use `ifdtool -x <resized_flash_image>` to extract the components.
The regions extracted can be used to generate a full flash image. The *bios* region is
not needed as this is replaced by the coreboot image.
NOTE: The gbe region contains the MAC address so be careful. When updating the flash using
flashrom it is advisable to leave out the *gbe* area.
## Flashing coreboot
### Internal programming
The SPI flash can be accessed using [flashrom].
The descriptor area needs to be updated once to resize the *bios* region.
`flashrom -p internal --ifd -i fd -w <coreboot.bin>`
After that only the bios area should to be updated.
`flashrom -p internal --ifd -i bios -w <coreboot.bin>`
The *gbe* and *me* regions should not be updated.
NOTE: As `flashrom --ifd` uses the flash descriptor it is required to update the
descriptor and bios regions in the right sequence. Don't update both in one command.
### External programming
The system has an internal flash chip which is a 16 MiB soldered SOIC-8 chip.