[LetuxOS] [Tinkerphones] LetuxOS: new updates

H. Nikolaus Schaller hns at goldelico.com
Tue Oct 5 19:07:03 CEST 2021

Hi all,
it is quite a while that there was an update what is going on.
So a lot of topics have been collected.

a) new Kernels letux-5.15-rc4!

Kernel development has progressed and we now have
letux-5.15-rc4. It is running quite stable now.

b) PVR SGX DDK 1.14 is working again!

There was an incompatibility introduced from upstream
that did break the DDK 1.14 somewhere between letux-5.6
and letux-5.10.

It has been possible to track and fix it as coming from
an untested and forgotten wrong compile fix in letux-5.8-rc1:


Now, the DDK 1.14 works again on omap3, 4 and 5.

DDK 1.17 unfortunately can't be tested because the
user-space binaries have dependencies that are
laying somewhere between Debian Buster and Bullseye.
I.e. Buster is too old and Bullseye too new.
To make it work again on Bullseye it would be required
to backport some package (I do not remember which
one but it can be researched).

PVR SGX on jz4780 is still a construction site since
we have no matching user-space code. Some idea very
long ago was to use qemu-arm on the mips machine to
run the arm-user-space. At least for testing if the
firmware can be loaded.

c) LetuxOS has got support for Raspi Zero and Zero W!

Thanks to Andreas Kemnade and David Boddie for support
(they gave the important hint that RasPi Zero uses an ARMv6
while all other devices have an ARMv7) it is now possible
to create an µSD that boots on the RasPi Zero or Zero W
with Debian Stretch (armel! only armel!).

The same µSD also works on RasPi 3B+ but there we can use

How to install (for example):

	makesd -vr stretch -vk latest raspi0 -r minimal

If you like you can enable boot logs by two sed commands
(also work on other RasPi):

	sed -i -e "s/BOOT_UART=0/BOOT_UART=1/" /media/letux/boot/bootcode.bin
	sed -i -e 's/quiet/ignore_loglevel/' /media/letux/boot/cmdline.txt 

Note that the Resulting system is pretty slow if you ever
had a comparison to some Cortex A15 (Pyra) or Quad Core
(RasPi 3B+).

But still it is useable but of course not inteded for
High Performance Computing.

The reason for the low speed is that it is a low clock
frequency single core processor limited by memory bandwidth.

By the way, Bluetooth also works. Just

	apt get install letux-firmware-brcm80211

WLAN ist also configured but wlan-scan does not report anything :(

To access the device, either use the FTDI console header
or some RNDIS/Ethernet gadget (root at on the
OTG USB port, exactly like for GTA04 or other LetuxOS devices.

And finally, even HDMI works.

Really interesting for an 5-10$ controller board.

One final note about other RasPi models. It is untested but
the raspi0 setup should also work on Raspi 1, 2 and 3.
Preferred for all Raspi 3 is to use makesd raspi3b+

RasPi 4 is not supported since it needs a different kernel.

d) Some older kernel builds are partially broken!

There was an issue in the build scripts so that the module.tgz
was overwritten by the version for Replicant. So beware if
you install some kernel binary from the downloads server between
ca. June and end of August.

All current builds have been checked and fixed.

e) Kobolino EPD driver!

Thanks to Andreas Kemnade (again!), we have a new
EPD driver that works really well - except two issues:
* screen is rotated by 90 degrees
  or there are redrawing glitches

This has to be studied further

f) CI20 (jz4780) gets HDMI support!

The driver is in the upstreaming process and reviewers had
interesting questions. These allowed to simplify the code
and even improve monitor support (I had two that were a quite
flaky but now it seems to work fine).

So it will need one or two more review rounds and then
hopefully it will be accepted by upstream maintainers.

g) Debian rootfs server tree reorganized!

The debian rootfs server got/will get a new structure
by adding a hierarchy level based on the year:


Currently, there is just 2021 but the plan is to manually
(or automatically) sort the older revisions into new subdirectories.

There will be (symbolic) links with "speaking" names, like


which means a Debian stretch rootfs for armel architecture
and preconfigured to include lxde.

There is also the "lastest" release which is currently

This is done to simplify control of makesd to install
what you want to have... makesd got new options:

	makesd -A mipsel -vr buster debian -r minimal

translates into "buster-mipsel-minimal.tbz"

Also note that bootloader and kernel and rootfs have
separate "version" options, i.e. -vb, -vk and -vr
so that you can for example take a mature and robust stable
bootloader with the latest kernel and a specific debian

Please note that I have tried to debootstrap Debian Bookworm
and Trixie but that fails for a missing certificate.

h) QuantumSTEP made multi-release!

QuantumSTEP for a longtime suffered from some fundamental
dependencies on basic library versions (e.g. libobjc, libjpeg)
which differ between e.g. Jessie, Stretch and Buster.

Instead of making QuantumSTEP for Jessie and QuantumSTEP for
Stretch and QuantumSZEP for Buster etc. we have developed
a method that only 3 packages really depend on the Debian
release and all others are "universal".

So this enables that we soon can have a release for an
intel based PC as well.

i) Issue with Let's Encrypt certificates expired on 30 sept 2021 solved!

Since some older root certificate expired on 30 sept 2021
there was no longer https access to download.goldelico.com
on Debian Jessie and Debian Stretch systems.

After long research sessions and (again) Andreas Kemnade
being lucky to giving the right hint, it can be easily fixed
on LetuxOS devices with this script:


You just have to download it to the device (well, that is difficult
since it itself uses https). So you should scp it. Then run once.

Or you can just copy&paste the sed command.

Please note that this is only for Jessie and Stretch.
Buster and beyond are not affected. They come with a different
set of certificates.

That's it for today :)

If you like this, please drop a note. If not, please tell
us what you prefer.

Happy Letuxing,
Nikolaus Schaller

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