[coreboot] Thin Client Compaq Evo T20

Juergen Beisert juergen127 at kreuzholzen.de
Fri May 23 18:09:45 CEST 2008

On Friday 23 May 2008 17:32, Philip Loewen wrote:
> Juergen Beisert wrote:
> > On Friday 23 May 2008 09:19, Markus wrote:
> >> Am Thu, 22 May 2008 23:58:35 -0700
> >>
> >> schrieb Philip Loewen <philip at tidepool.ca>:
> >>> Right now I only know how to access the 48M of onboard flash
> >>> memory in this little box using the proprietary tools that
> >>> run in the proprietary BIOS. If I replace the BIOS with
> >>> coreboot, I will need some other way to access the NAND
> >>> flash memory. Is there a known working method for this that
> >>> runs on Linux? (I have tried adding support for Memory
> >>> Technology Devices to my kernel, but I don't know how to tell
> >>> if they are working.)
> >>
> >> On my Evo T30 the internal flash works as an hda Disk. The only bad
> >> thing on this. The fist partition is needed from the proprietary Bios.
> >> Are you able to boot an Linux and take a look?
> >
> > This kind of NAND devices (DiskOnChip in my box) provides a simple BIOS
> > extension. They hook themselves into the boot interrupt of a proprietary
> > BIOS. So they can emulate a harddisk to boot from. IMHO for coreboot we
> > need a different solution.
> Linux kernel 2.6.24-gentoo-r4 runs well for me, but I don't
> know where to look for internal flash memory access. There
> are no disk-like devices listed in /dev. (/dev is populated
> automatically by udev at boot time ... but being a gentoo
> user means never feeling quite sure everything is configured
> right.) The file /proc/devices shows 16 block devices of
> type 'sd': I don't know what these are, but none of the
> other possibilities listed in /proc/devices seem likely to me.

"sd" are scsi hard disks, also used for all USB based mass storage devices.
I think your kernel has no support for the DOC device. Else there should be 
some or at least one /dev/mtdblock? device(s) exist.
Check if your kernel has the follwing symbols enabled:
 - CONFIG_NFTL (for a generic filesystem) or CONFIG_JFFS2_FS (flash specific

If yes, you could try to load one of the DOC drivers and see if one is able to 
detect the DOC in your system.


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