[coreboot] Lenovo X220t variants with SMD-Flash-ROMs
Igor Skochinsky
skochinsky at mail.ru
Sat Aug 5 21:12:25 CEST 2017
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
--
WBR,
Igor mailto:roxfan at skynet.be
More information about the coreboot
mailing list