David Given dg at
Thu Sep 14 06:59:23 EDT 2000

>Yep.  It will do.  The CFI probe stuff thinks that each chip is 2
>interleaved => it thinks the size of the chip returned is half the
>actual size.  It then looks for the second chip at two times the size
>returned ie 8*2=16Mibyte => it can't find the second chip.  I fudged
>around this by ignoring the interleave when working out the address to
>probe for a second chip.  This isn't in the CVS since it would break
>other peoples chips.  I've reasly got to think of a better solution...

I don't know enough about the way flash works to determine what's going on, 
I'm afraid.

>They're not really partition but MTD devices that are restricted to
>certain areas of the flash.
>The odd numbered devices are read only versions of the even numbered
>devices which is why mtd0 looks the same as mtd1.

Am I right in assuming that the partition sizes in sbc_mediagx.c are 
hard-coded and don't necessarily correspond to any particular region on the 
disk? FXINFO claims that the VBF partition starts at 256kB. Looking at 
dev/mtd/0, there's a ROM image in the bottom 8kB, and at 256kB there's 
something that looks suspiciously like a VBF header. I can certainly identify 
things like the volume serial number and various pieces of information that 
FXINFO gave me. These are then repeated every megabyte.


Yup, changing the partition information to:

const static PartitionInfo partition_info[]={
    {"SBC-MediaGX flash BIOS extension", 0, 256*1024},
    {"SBC-MediaGX flash VBF volume", 256*1024, 0},

...makes things make a whole lot more sense.

>You won't beable to have both Linux and Dos booting of the flash.  Just
>make sure you have a floppy drive to boot from...

I have one, yes. However I'm extremely wary of playing with the flash; as far 
as I can determine, the FlashFX BIOS extension and, possibly, the Award BIOS 
itself are in the flash. If I erased it all from within Linux, I might nuke 
those as well and render the board unbootable. If anyone can comfirm that this 
is not the case, I would be most grateful.

Am I right in assuming that VBF is patented and closed? Is any information on 
it at all available, even just enough to identify the start of the VBF 

>Arcom is currently in the process of producing a Linux dev. kit which
>will do all this + booting for you.


David Given
dg at

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