[Arm-netbook] microdesktop casework as DXF files for laser-cutting

zap zapper at openmailbox.org
Mon Apr 3 00:50:01 BST 2017



On 04/02/2017 06:17 PM, Luke Kenneth Casson Leighton wrote:
> On Sun, Apr 2, 2017 at 10:51 PM, zap <zapper at openmailbox.org> wrote:
>> I am really though glad you take this sort of thing seriously. We should
>> all thank you for such zeal towards keeping things "Libre"
>  mmm... zeal's a dirty word, now :)
My bad...

>> I hope you are successful Luke. And really, if normand sees this post, I
>> hope he has a better understanding of the consequences of such actions.
>  let's hope so
>> Anyways though, I look forward to when you get the rockchip processor
>> working to your specifications.
>  i'll be happy it works _at all_!

I am sure you will figure it out sooner or later.

>> One last thing though, you said the a20 doesn't support 4.9 kernel...
> correction: it does... but not with 100% hardware functionality
> supported (which is no good for what i promised and demonstrated in
> the updates)
>
>> but what about the rk3288 processor?
>  mainline for everything.  u-boot, kernel - everything.  it's been
> that way for some considerable time.
>
>  i'm still struggling with reverse-engineering the proprietary DDR3
> 200mhz initialisation binary, working out what the discrepancies are
> between that and u-boot.  it doesn't help that i don't know if i
> soldered the processor on incorrectly or any one of the four 96-pin
> DDR3 RAM ICs...
>
>  i've bought a stack of cheaper RAM ICs with which to experiment:
> they're the same ones as on the RK3288-Firefly so in theory i should
> be able to use exactly the same dtb file for the dram settings...
> except the damn impedance is only (appx) 50 ohms not 100 like it is
> for a 6-layer 1.6mm PCB...
>
>  basically there's too many unknowns in order to triangulate exactly
> where the problem might be when any one of them could be the source of
> the failure.
>  at some point i'm just going to say "fuck it", work out how to load
> the proprietary DRAM initialisation, then u-boot with DRAM
> initialisation *disabled*, work out how to get the RK3288 *out* of
> DRAM initialisation mode and to continue running u-boot.
I am hopeful you will succeed in reverse enginnering the rk3288.

>  apparently the internal ROM USB-loader can be asked to "shift"
> whatever's loaded down into a different address in memory, but how
> it's then executed i don't know.
>
> l.
>
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