[coreboot] SPI flashing

[Andreas Galauner]

Hello again,
as you may have read yesterday, I'm currently trying to play with some
in-system SPI flashing and I need some additional advice.

I just soldered a Pinheader to an Intel D525MW Motherboard
(http://www.dont.ru/i/img_1orig/129310882576.jpg - lower right corner)
I'm currently not using, but I'm not sure if I should really connect
some hardware to it and pull/push on the SPI lines.

I suppose it's generally a bad idea to do this, when the Board is
currently operating. If it is completely off, I can supply external
power and just flash, right?

And what about the reset state? I don't have any schematics of my
motherboards, so I don't know if there are pull-up or pull-down
resistors, I don't know if the chipset really switches its SPI lines
into a Z-state, if it is held in reset and so on.
I don't want to let the magic smoke escape from my motherboard ;)

The only thing I found out is, that the HOLD# ("pauses" the flash chip)
and WP# are connected to VCC over a 150 Ohm resistor, each. 150 Ohm is
too low for a pull-up, so these two seem to be for limiting the current.

Also the pinout is kind of "weird":
1	#CS
2	#CS
3	SI
4	NC
5	SO
6	VCC
7	SCK
8	GND

Why is CS# connected to two pins? The resistance between those two pins
is 1 Ohm, so they are connected directly. Interestingly the are
connected through a 0 Ohm resistor. Any ideas on that?

Are there some kind of "best practices" the vendors have when designing
those in-system-SPI-flashing-headers? I mean they have to flash these
boards in some way by themselves without sending them to heaven, if
there is an SPI header.

Any advice is greatly appreciated.

Thanks,
Andreas