As both of serial flash chips on Red Fort CRB are Atmel's AT26DF321
Checking Atmel's AT26DF321 Datasheet (page2 to page3)
you can find out it's Hold Pin in NC
that's why there is no way to use "voltage divider principle" on hold pin to
disable on baord SPI flash part and replace with emulator
(that's why even test clip with replace function will not work on it)
the only way is desodering AT26DF321
after desoldering, you can see the footprint with SO8W and SO16 dual layout
so just soldering 1.27mm pitch 2*4 pin head on CRB and then you can connect emulator easily.
As everyone would prefer like to preserve CRB in origin status,
may need to double check with own design board in the future.
in fact, it's really inconvenient to desolder and soder serial flash chip back to to test and verify.
If so, you can try this accessory--SDW0016AA
SPI S016 socket to 1.27mm 2x4 female head
after desodering, put the unmounted AT26DF321 in to SO16 socket
connecting the SDW0016AA on CRB, you can use a real serial flash chip to tesk and verify.
after removing it you can connecting SPI flash emulator conveniently.
To support 2 serial flash chip you will need two SDW0016AA
When SPI flash emlator emulates 1 serial flash chip, the red extend line will be "reset" function, please do not connect to this pin.
If firmware upgrade to emulate 2 serial flash chip function(share same SPI bus)
then the function of red extend line will change from "reset" to "CS2" and then you can connect to CS2 PIN on CRB.
Easily to meet your development reqirement with emulating 1 or 2 flash chips with one emulator.
And it is really convenient for your working on frequently test and verify.
Finally if you need to return CRB back to INTEL, just desoldering pin head
and soldering serial flash chip back will be OK.
(from beginning to end you just need to desoder and solder for twice)
with SDW0016AA, to test on other vender's serial flash chip will be easy than ever.
Just putting different vendor's serial flash chip in to socket and connect to pin head on CRB to test and verify directly.
