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

[Alexandre Boeglin]

Le jeudi 08 mai 2014 à 00:23, Stefan Tauner a écrit:
> We could add a programmer parameter and let the user decide/override
> until we understand this better. Does the DDC tunnel still work with a
> broken firmware or is an external programmer needed if the first try to
> modify the firmware fails and the SoC inside the device is reset?

Well, it seems it depends. One user of this mstarddc programmer had an
error during the write operation due to (it seems) an I2C driver working
at less than half of the normal 100kb/s I2Cspeed, but even after
power-cycling the screen, he managed to successfully reflash it using
another laptop.

But in the mean time, the screen was not working properly, and I'm
guessing it was maybe in some kind of emergency mode, maybe an
in-silicon bootloader that allows access to the ISP port.

OTOH, another person, using the "official" MSTAR tool was unable to
reflash his screen after the initial failure. But I didn't get him to
try the programmer I wrote, so I don't know for sure what his problem
was (maybe even just a bug in the official tool).

Anyway, I slightly modified the programmer in the patch revision I sent
this morning. It does not send the reset command (which causes the
screen to exit ISP mode and re-read the flash firmware) if an error
occured. So, as long as the screen remains powered, another attempt can
be made.

But then, with the limited amount of info I had, most of it is just
guesses.

Best regards,
Alex
-- 
Alexandre Boeglin
email: alex (at) boeglin (dot) org
jabber: alex (at) im (dot) boeglin (dot) org
website: http://boeglin.org/