[Arm-netbook] Side-Topic: Liberating PocketCHIP

[Pablo]

This is a quite late reply to some Emails on this list from May. I took some
time to research and test. 
John, do you still work on liberating Pocketchip?

Good news is that I managed to install Debian
Stretch (current stable) with Debian Installer on a USB-stick. The CHIP
OS based on Debian by NextThing is completely left alone.
I plan to write a tutorial to document my approach and will put it on the Debian Wiki.

On Sat, May 13, 2017 at 01:13:39AM -0400, John Luke Gibson wrote:
> On 5/12/17, Louis Pearson <desttinghimgame at gmail.com> wrote:
> > I don't know if you know about this or not, but there is a community
> > wiki at http://www.chip-community.org/index.php/Main_Page
> > It has examples on using buildroot to flash images to chip
> > http://www.chip-community.org/index.php/Flashing_Buildroot_Image_from_Ubuntu

I knew about the community wiki. In my opinion Chip has a great,
friendly and helpful community. I am not going to blame the community -
especially because I have not yet found the time to contribute to the
community wiki. My critique was directed at the manufacturer
NextThing Co.

John mentioned that he will have a look at the kernel first and later at
U-boot. I have found some additional documents. To replace the existing kernel there is no need to reflash.
A very good tutorial can be found here:
http://www.raspibo.org/wiki/index.php/Compile_the_Linux_kernel_for_Chip:_my_personal_HOWTO#My_config_file

...and also a way to test a new kernel in a save way. Keep your
USB-to-serial-cable ready in case things go wrong:
http://www.raspibo.org/wiki/index.php/Chip9%24_U-Boot:_how_to_test_a_new_kernel_%28in_a_safe_way%29

> > Found the wiki up there through some searching. This is my
> > first foray into working with embedded linux devices as well.
> 
> I knew about the wiki, then again I believe someone else was asking
> about one earlier.

Yes, it was me. 

> I'm still wrapping my head around these make scripts to make sure
> nothing proprietary is hidden anywhere they don't theoretically need
> to be.
> Probably a good idea to use mainline libre-linux, but first want to
> make a diff file comparing their fork with libre to make sure their
> aren't any drivers which are libre that we might need (or any
> bug-fixes). 

There is a deblob script used by Parabola Linux to liberate a mainline kernel. It is used to
create a libre-linux kernel from mainline.

> 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.
I had some problems to boot the rootfs after completing installation and
solved it with help from the debian-arm mailing list (see this thread
for additional information:
https://lists.debian.org/debian-arm/2017/06/msg00027.html)
I am only using Debians main repos and connect to the Internet via
USB-OTG with the g_ether kernel module and a network bridge on my
desktop.  
This is libre enough for me. 
I am running Chip headless via ssh and have not tested video and
sound yet. There may be some hidden quirks I am not yet aware of but so
far it looks good. 

kind regards
Pablo