[coreboot] Flashing Coreboot on Lenovo G505s

[Mike Banon]

Thank you for the kind words, Anac ;) another "CH341A advice": check
its' voltage before using for the first time, because there were a few
CH341A (the majority of reports were about black PCB version) , which
- because of manufacturer's mistake - supply 5V power instead of 3.3V
and that could damage your BIOS chip. (btw its' possible to repair
these CH341A to make them 3.3V, seen the rework instructions somewhere
online). Although the probability of getting such faulty CH341A is
very small, maybe its' better to buy CH341A with green PCB to be a
little bit safer (don't know about blue PCB) , and just in case -
check the voltage between power VCC and ground GND before the first
usage.

By the way, these short wires you've seen at my photo - are a bit of
an overkill and not so convenient to use. 10cm copper is enough for
the majority of tasks, I've created these custom 5cm in an attempt to
have the better flashing results with some "current-draining" hungry
boards - G505S LA-A091P / LA-A092P , like the majority of other laptop
boards, is not one of them. For many people even their 20cm aluminium
wires are enough (they come together with the cheapest SOIC8 test
clips as soldered to them) - and 20cm aluminium is like 30cm copper in
terms of electrical resistance
On Tue, Sep 25, 2018 at 3:36 PM Anac <anac at rbox.co> wrote:
>
>
>
> On 09/24/2018 12:37 AM, Mike Banon wrote:
> > Hello Anac! I am "mikeb" , wrote these BIOS / KB9012 flashing articles
> > at DP wiki ;-)
> Thanks a lot for that work, your support and sharing all the super
> useful info and hints here!
>
> > Operating CH341A is very easy: I wrote the instructions for Bus Pirate
> > because of its' confusing pinout, and thought CH341A pretty is
> > obvious. But, seeing there are requests like yours from time to time,
> > finally I've expanded that flashing article with two extra photos,
> > they should explain everything -
> > http://dangerousprototypes.com/docs/Flashing_a_BIOS_chip_with_Bus_Pirate#CH341A_flashing_coreboot_open_source_BIOS_to_Lenovo_G505S_hacking
> >   You just need to make sure that the pins of your programmer and chip
> > are matching each other, e.g. CS - chip select. Also, remember to
> > disconnect all the power sources from your laptop (both battery and
> > power adapter) and before plugging the programmer into USB you need to
> > connect its' SOIC8 clip, and after the flashing you disconnect USB
> > first and SOIC8 clip second.
> Yes, for someone who has never done it, that sort of info is priceless.
> Just like your advice to put insulation tape at the
> bottom of CH341A - it may even save hardware from getting fried
> (thinking of short cables, big fingers, SOIC clip sliding off the chip
> and all).
>
> Thanks to Awokd, Matt and Nico, too. And of course to Taiidan for
> promoting the G505s.
>
> Sincerely,
> Anac