[flashrom] [PATCH] Add programmer for the MSTAR I2C ISP protocol

[Stefan Tauner]

On Sun, 4 May 2014 18:20:04 +0200
Alexandre Boeglin <alex at boeglin.org> wrote:

> Hi,
> 
> Here is a patch, that provides support for the MSTAR ISP protocol.
> 
> Basically, among other chips, MSTAR manufactures SoCs that equip TV sets
> and computer screens, and it seems that all of their products use the
> same in-system programming protocol. Basically, they use the DDC channel
> of VGA or DVI connectors, which is actually an I2C bus, to encapsulate
> SPI frames (the flash chip is connected to the SoC through an SPI bus).
> 
> I wrote this patch since the screen I bought had a software bug, and the
> manufacturer only released a new firmware binary, but no tool or
> instructions on flashing it.
> 
> More details can be found here:
> http://boeglin.org/blog/index.php?entry=Flashing-a-BenQ-Z-series-for-free(dom)
> 
> I only read code from Linux kernel archives published by Acer to figure
> out the protocol (for a touchscreen controller and a NFC chip, both by
> MSTAR, that shared the same ISP protocol), so I don't think there are
> any legal problems with it.
> 
> Please let me know what you think about this patch, and whether you're
> interested in including it.
> 

Hello Alexandre,

that's a hilarious story, thanks for sharing! I just skimmed through
your blog post but it really looks like an awesome RE experience, and
the whole tunnel flash access is just insane :)
I would really love to include this just because of that... I am not
so sure if it would be useful to many... OTOH one of our community
members immediately popped up his screen after reading your story... and
found a MSTAR chip and a flash and already got it to probe successfully,
so... :)

I did not carefully review the patch yet, just a few remarks:
- We need a proper sign-off from you to include the patch, see
  http://www.coreboot.org/Development_Guidelines#Sign-off_Procedure
- I'd like to have at least a dedicated paragraph in the manpage that
  gives some background information, and some explanation regarding
  the dev syntax of course.
- The coding style does not completely follow ours, e.g. the braces
  after ifs should be on the same line.
- The progress print needs to go, I think. It has been decided long ago
  that we either do this right(tm) or not at all. flashrom should never
  go into infinite loops and it should also not be interrupted, hence a
  progress bar is only a placebo, he just have to be patient.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner