On 25.11.18 01:30, moriel5 via flashrom wrote:
The schematics refer to 2 SPI chips, an 8MB
W25Q64FVSSIQ_SO8 on UC3 as
the main SPI chip, and an 4MB W25Q32FVSSIQ_SO8 on UC6 as backup.I have
only one SPI chip, an 8MB W25Q64FVS1011532 on UC3, with the UC6 solder
point existing, so I could theoretically solder a backup SPI chip.
It's probably not that easy. You'd need a way to switch between the
chips. But there may still be use for these pads, see below.
The IdeaPad 300-15's motherboard is codenamed
Didn't find anything by that name, but found some "BMWQ1/Q2" that
matches your description and is sometimes mentioned along the IdeaPad
Can anyone help me with my research? I'm still not
very experienced with
the actual work regarding electronics, most of my experience is with
researching them.If there is any more information required from the
schematics, I'll gladly share them,
What I found were only highly compressed, low resolution pictures of the
schematics with hard to read net names. But it seems the 8MiB flash is
shared between the Skylake SoC and the EC. In the most discouraged way:
they are both directly connected as SPI master. Alas, this is sometimes
done because there is money to save.
If my assessment is correct, flashing this board with an external flash
programmer will be a most delicate procedure. There are some options,
1. Desolder the flash chip, put an isolation circuit between the chip
and the board.
2. If the CS# line of UC6 is only connected to the SoC but not the EC,
you could put an isolation circuit plus extra flash chip there.
3. Same "If", but with the chip on the board and an isolation circuit
between the flash and the programmer. Might make it easier if you
want to close the laptop's case. In this case the CS# line of UC3
should control the isolation, so the EC could always take over the
bus and talk to its flash.
4. Rather discouraged: Ignore the EC and add yet another master to
the SPI bus (i.e. connect the programmer directly). Usually you are
lucky and nothing breaks. But in rare cases you can confuse the EC
and cause permanent damage.
To sum it up: If you don't have isolation between the mainboard and the
programmer, the EC will be awake during flashing and you'll have to take
care somehow (or take the risk).
and if anyone wants the schematics, I can send them
I wouldn't mind.