[Arm-netbook] Side-Topic: Liberating PocketCHIP

[doark at mail.com]

On Tue, 11 Jul 2017 12:10:21 +0200
Pablo Rath <pablo at parobalth.org> wrote:
> On Fri, Jul 07, 2017 at 06:19:29PM -0400, David Niklas wrote:
> > On Thu, 6 Jul 2017 13:21:56 +0200
> > 
> > Actually, my PC has a kernel fault   
> 
> It took me a moment to guess that you abbreviate PocketChip as "PC". My
> mind went like: "What? Why is he talking about his Personal Computer
> now?" :)

The pocketchip community uses that abbreviation frequently, it confuses
me sometimes too.

> > (It's a long story of ntc's evil
> > doing),   
> 
> Why do you believe that ntc is evil?

When you boot a normal Linux computer you are presented with a plymouth
boot screen and can hit escape to exit and see the boot messages.
I pocketchip's case you are presented (serendipity), with a boot screen
that somehow references a file listed in /home/chip (I forget the
exact name, it starts with a period), that invokes feh on pocketchip's
logo boot screen from which there is no escape. If you uninstall plymouth
and delete the file that invokes feh in /home/chip you are just presented
with a black screen.
Once pocketchip finishes booting you cannot use Alt-F[0-9][0-9] to switch
tty's, nor can you use Ctrl-Alt-F[0-9][0-9], so if the boot fails for any
reason you are stuck with never being able to fix or diagnose it (though
you might get the last few messages of some error, which you might have
read in full if the screen was not black).
I asked in to forums about how to solve this and it's been weeks without
any answer (I only ever got one, and that user told me not to side load
software (which I explained that I never did or even thought of)).

> > and the Linux kernel claims that it is not tainted.
> > I don't know if that covers firmware, but at least there are no
> > modules that are non-free.  
> 
> I don't understand the paragraph above. Do you talk about mainline linux
> kernel, ntc's kernel fork for Chip, ... Can you please clarify?

The kernel is the default and it's name is:
4.4.13 ntc mlc

> > > > Best bet is to use libre-linux mainline and besides that just
> > > > attempt to deblob ntc's components by hand, which shouldn't be a
> > > > problem long term cause it doesn't look like they maintain any of
> > > > this stuff at all anyway and it's very likely the only blobs are
> > > > in the kernel anyway however not a sure one.  
> > > 
> > > I ditched all the custom NTC stuff and went for vanilla Debian. I
> > > have managed to install Debian Stretch (current Stable) on a USB
> > > stick using Debian Installer. I am using a self-compiled mainline
> > > U-Boot via sunxi-fel to circumvent the U-Boot version on NAND
> > > provided by the manufacturer which can not boot from USB.  
> > <snip>
> > 
> > I've found two faults that cannot be traced without a postmortem and
> > I'm really sick of accidentally causing this thing to manifest said
> > problems and then loosing all the work that I did in between my
> > backup periods.  
> 
> How can you be sure it is a kernel bug and not another problem?

Can't, that's why I'm in this predicament. All I know is the last few
messages that say that the kernel is not syncing with the rootfs (and I
have not touched the partition table, or init, or those scripts and files
(like fstab), which would alter the mounting process).

> Can you
> give us some details. Did you ask on ntc's user forum or did you file a
> bug report 
2. Asked on the forum (I was a bit exasperated at the time since FLOSS
software is no good to me if I can't debug it).
Here are the post (hmm, seems that email notification of new replies is
not working:
https://bbs.nextthing.co/t/pocketchip-boots-to-black-screen/14643
https://bbs.nextthing.co/t/kernel-panic-not-syncing/17525

> Can't you improve you backup strategy - for example commit
> to an external git repo; or synchronize with another stable working
> computer?
3. Not really. I use pocketchip on-the-go and typically what I'm doing on
the go is offline and I'm physically separated from my other machines.

> > I'm in need of a way to boot PC without flashing the NAND I there a
> > way to do this? So far my search results have been unsuccessful.  
> 
> 1. Well, you can take your Chip out of the housing and install the
> distro of you choice on a USB-stick and use it as a regular Chip.

I thought chip could not boot via usb?

> 2. Can you get PocketChip into fel-mode without taking it out of the
> enclosure? Ntc's documentation claims it is not possible but there is a
> forum thread about a reboot option into fel-mode. I have no PoketChip
> and leave it up to you to research the answers to this questions.

I think I could but then what? I know repetitively little about FEL mode
(though I'm willing to learn).

> Another point is if the distro of you choice on a USB-stick will support
> PocketChips hardware (e.g. Keyboard, LCD-Screen) out of the box. Do you
> have a serial-to-usb-cable to interact with PocketChip?

I don't think so. But it's confusing when people write things like that
because USB stands for Universal *Serial* Bus (so USB is a serial
cable and no conversion is needed!).

> 
> kind regards
> Pablo 
> 

Thanks Pablo,
David
t