pxe boot of chromebox 3 (probably requires relacement coreboot firmware)

[lkcl]

hi folks,

at work we bought a couple of samsung chromebox 3 devices to review for use as a low-cost easy-to-drop-in replacement for a rather expensive setup involving Mini-ITX motherboards that are rapidly approaching end-of-life.  at £250 all-in, the chromebox 3 is perfect: only 16gbyte SSD (we don't need more), low profile - perfect....

... with the exception that the BIOS has been set up to be completely impractical as far as remote management is concerned.  pull a switch?  press ctrl-d or wait 30 seconds?  no PXE boot?  pull my leg instead, it's got bells on :)

so i'd like to investigate doing a rebuild of coreboot for the chromebox, and this page says "warning, warning, it's dangerous, so we might document it later" which doesn't reaally help those people actually willing to risk trashing the box - it leaves them in a position where they *really* are *more* likely to do harm if they attempt anything:

   http://dev.chromium.org/chromium-os/developer-information-for-chrome-os-devices/custom-firmware

so - question: where is the GPL source code for coreboot for the samsung chromebox 3, so that i can add PXE boot and some form of serial (USB, RS232, Ethernet) access to the BIOS at boot-up?

also: is there an RS232 header or JTAG header anywhere on the PCB, not so much just in case but also so as to be able to connect a standard RS232 COM port to a remote management board?

many thanks,

l.

[OBoyle, Daniel]

A PXE boot native to those devices would be GREATLY appreciated.

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Dan O’Boyle

Senior Systems Engineer

Hillsborough Township Public Schools

908.431.6706 dob...@htps.us

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[Hung-Te Lin]

On Fri, Mar 15, 2013 at 8:34 PM, lkcl <luke.l...@gmail.com> wrote:

   http://dev.chromium.org/chromium-os/developer-information-for-chrome-os-devices/custom-firmware

so - question: where is the GPL source code for coreboot for the samsung chromebox 3,

 

  It's already in official coreboot source tree ( http://www.coreboot.org/Download_coreboot ).

  Just select "samsung/stumpy" mainboard configuration.

[lkcl]

fantastic - that was the codename i needed to know.  ok, so next question: where are the installation procedures [the ones missing from the link above] that will allow writing of the firmware to the BIOS, and also how is it possible to read the existing BIOS

and, also, the other follow-up question: if building and selecting just the defaults for all configuration options, will the firmware that is produced be *exactly* the same binary as that which is installed on the production devices?

what i would like to do is to get an exact verifiable build, before moving on to trying an alternative firmware with absolute minimum changes.

thanks hung-te.

l.

[Mike Frysinger]

On Fri, Mar 15, 2013 at 12:14 PM, lkcl <luke.l...@gmail.com> wrote:
> ok, so next question:
> where are the installation procedures [the ones missing from the link above]
> that will allow writing of the firmware to the BIOS, and also how is it
> possible to read the existing BIOS

you have to take apart the case and set the write protect jumper.
there was a thread on this list sometime ago where people posted
pictures and the jumper was pointed out.

you can use flashrom that is shipped with ChromeOS to read & write the firmware.

> and, also, the other follow-up question: if building and selecting just the
> defaults for all configuration options, will the firmware that is produced
> be *exactly* the same binary as that which is installed on the production
> devices?

of course not. you aren't using the same toolchain, and upstream
coreboot has been adding features/changing code over time.
-mike

[Hung-Te Lin]

> what i would like to do is to get an exact verifiable build...

Also, if you want to get a build doing similar things as current shipping firmware does,

as you can find in the "Custom Firmware" doc, Stumpy uses Coreboot + U-Boot.

That means you also need to build a U-Boot and merge them together into one ROM image.

Those steps were made by chromeos-u-boot and chromeos-bootimage ebuild in chromiumos source tree.