[LinuxBIOS] RD1 BIOS Savior [was Re: No known linux compatable BIOS programmer ?]

Richard Smith smithbone at gmail.com
Wed Aug 17 20:29:55 CEST 2005

> > I'd certainly be willing to make a go of it. If I can dig it up, there
> > were some guys that wrote a parallel jtag interface to program amd
> > flash. Maybe it would be useful. That was several years ago and the site
> > seems lost in the annals of history now. Maybe you wrote that too :)
> Cool.  I'll stick the software somewhere useful.

If you are really up for a challenge that involves a bit of RE.  Then
let me sugggest the batronix
http://www.batronix.com/electronic/index.shtml programmer.

This weekend I spent some time working with it and linux.  The device
has a USB Cypress an2131s.  The device firmware is downloaded into the
device and linux has all the tools to do this.   I was able to build
and dowload and the usb-test code and it sort of worked.  I need to
code up a bit toggle and see if I can get that to happen and verify I
_really_ am running my firmware.  I've grabbed the datasheets off of
cypress's website and I have the example test code so this shouldn't
be too hard.

The unit is basically a bunch of latches and bus drivers that are all
on some sort of make shift address/data bus.  I beeped out a lot of
the connections to the latches and although it will be a lot of work
it looks workable to RE all the connections to the programming socket
and how to drive it.

Some USB sniffing software should also help me figure out a few
things.  Perhaps I can figure out how to  get it to work with the
firmware(s) that come with the doze software.

> Sadly, having fixed the regulator, I'm still stuck with the problem getting
> data off of the EPROM.  I've tested  the 4014 read circuitry (and software)
> by hot-wiring various EPROM-ZIF output bits to gnd or +5v and checking the
> output: this works correctly.  Addresses are clocked in OK.  Both /CE and /OE
> are low, yet the output is neither correct (well ... believable) nor
> consistent.

In the past when we have blown up various things like this some of the
latches or bus drivers were also damaged.  They may appear to work but
fail when you load them real world.

When you toasted the regulator could you have overvoltaged Vcc?  If so
then every active part on there is suspect.

Richard A. Smith

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