Yes, this is often done as a cost reduction method. The habit started with the arrival of the ME and the firmware descriptor allowing you to spread your different firmware regions across one or both chips. The tool ifdtool will help you analyze images for Intel firmware descriptors. Sounds like in this case ME and the other regions live in the larger chip, allowing the smaller chip to be fully used for system firmware. If that's the case, erasing the larger chip will brick your system. Better do some analysis first.
Stefan On Mon, 16 Sep 2019, 04:50 Philipp Stanner, <[email protected]> wrote: > Hi folks, > > Platforms like the x230 have two flash ROMs which are virtually treated > as a single one. > > So: > 1. What the heck is the meaning of this? Why do vendors buy and solder > two small chips (even worse, on the x230, one with 8M and one with > 4M) instead of a single big one? Is this cheaper? Sounds unlikely to > me, in technics one big thing is usually cheaper than several small > ones. Beyond that, I imagine you have some effort to concatenate the > two chips virtually. > 2. The manual for the x230 [1] (is there a version in the new > documentation btw?) states that you can just flash the smaller (4M) > chip and then you're done. So I assume: > 1. the 4M chip is the one the CPU first executes code from > 2. neither coreboot nor the payload will ever jump "into" the larger > chip, therefore code from it will not be executed. > 3. Therefore, it does not matter if you overwrite the 8M chip or > not. > > But what lays on this larger ROM? What if there are parts of the IME on > it I would like to annihilate? > > The whole thing is really awkward to me. Especially, because the > predecessor x220 already has a place on the board ready to host the > second chip, but it was left empty on this device. > > P. > > > [1] https://www.coreboot.org/Board:lenovo/x230 > _______________________________________________ > coreboot mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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