This information is valid for all supported models, except T430s, T431s and X230s.
+---------------------+--------------------------------+ | 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 | +---------------------+--------------------------------+
Please also have a look at :doc:`../../tutorial/flashing_firmware/index`.
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.
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
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.
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.