[Letux-kernel] New LetuxOS Kernels and some tricks and thoughts

H. Nikolaus Schaller hns at goldelico.com
Tue May 21 10:22:50 CEST 2019

there are new LetuxOS kernels:


Please see:


Unfortunately display drivers in letux-5.2-rc1 for almost all devices are broken. So please either help
to fix the issues or wait for a later -rc.

Just in case you are not aware, letux-4.19.44 is the current longterm kernel and recommended for daily
use on our devices. You can also install it in LetuxOS Debian systems through

	apt-get install linux-image-letux linux-rootfs-letux

and then an

	apt-get update && apt-get upgrade

is sufficient to get future kernel (and other) updates.

BTW, here is another trick: You may (not) know that LetuxOS images created by makesd come rooted.
This means you can simply ssh as root into the device without password check. This is quite helpful
for developers and debugging.

You can just do

	apt-get remove letux-ssh-root

to disable. Or apt-get install letux-ssh-root to re-enable. The latter of course means that you still
have some root access to the device. Either through sudo or the serial console.

What else is going on in the LetuxOS eco-system?

We now support MIPS devices, not only ARM. Well one. The Imagination CI20 board. Just do "makesd ci20" to
get a first SD card.

Behind the scenes, we have debootstrapped mipsel variants of the Letux Debian images. And adapted the
kernel defconfig so that we get a CI20 (Ingenic JZ4780) compatible kernel.

What is the motivation behind supporting yet another board (and not fixing all others first)?
The main aspect is that the jz4780 also contains an SGX 544 GPU - like the OMAP5. This should help to get
the SGX drivers working.

The other aspect is that "fixing all others first" is a Sisyphus work. It is a never ending story. So
we can't wait until it is done. It will never be done ;) Therefore better contribute what can be done.

Finally, we have built a second generation (mechanical) prototype of the GTA15, the PyraPhone.
Some photos can be seen in the twitter channel


and ED has made a nice video showing the Pyra and explaining the GTA15 board:

	https://youtu.be/X3Su8LJnmd4 (GTA15 presentation is starting at 14:07).

Both devices can share almost the same software, so there is a big synergy between both projects.

Note that although it looks almost finished, this is just a mechanical protoype to find out if it can
be built and if components are on good positions (almost all are, some are not that good). The PCB
traces are incomplete which means that connecting a battery has no effect :)

On a very general view, we have achieved a lot, but still not enough to get the LetuxOS eco-system
into a self-sustaining mode. What is lacking?

* users are missing because software is not good enough for daily use
* hardware is missing because potential users complain about missing high-quality software
* developers to polish the software are missing, because of missing (new) hardware

You see the vicious circle? Ideas how to magically break it?

BR and happy tinkering,

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