[coreboot] Lenovo X220t variants with SMD-Flash-ROMs

[Philipp Stanner]

Do we have any idea what exactly they do to update the firmware internally?

The wiki says once coreboot is flashed you can flash it internally. I
suppose this means the blockade protecting the flash can be switched of
somehow, as the vendor's have to do it to install firmware-updates.


Am 05.08.2017 um 21:12 schrieb Igor Skochinsky via coreboot:
> Hello Philipp,
>
> Saturday, August 5, 2017, 8:41:42 PM, you wrote:
>
> PS> Yes, you're probably right.
>
> PS> Though I wonder when and how they programmed the firmware. Before or
> PS> after soldering?
>
> Most likely before, unless they have some debug header exposed. From
> [1]:
>
>> When the hardware and software nears production readiness, it is
>> common practice to preprogram flash memory devices prior to
>> starting high-volume PCB manufacturing flows for two principal
>> reasons. First, firmware loaded onto the device can be used to
>> perform basic booting and testing of the PCB during manufacturing
>> to check system/module functionality. Second, loading the final
>> firmware, operating system (OS), and application code on the flash
>> device prior to manufacturing maintains a high-volume
>> manufacturing beat rate. To support these usage models, multiple
>> vendors provide systems for loading firmware and data into flash
>> memory devices prior to the PCB solder flow process.
> Modern flash chips don't have issues retaining programmed bits during reflow
> soldering as long as the correct temperature profile is observed [2].
>
> [1]: http://www.electronicdesign.com/memory/understanding-onboard-flash-programming
> [2]: http://dataioinfo.com/LiveImages/26/20/DocumentURL.pdf
>
>
>