Recovering Serial Connection on FRDM-LS1012A

During a recent workshop, I observed a strange interaction between Windows 10 systems and the serial connection to an NXP Freedom LS1012A board already referenced in one of my previous posts (Bootstraping Debian 9 (Stretch) for arm64). Due to this interaction two boards were rendered useless during the workshop.

This post explains the problem and shows how to easily recover the boards with the matching firmware for the serial to USB converter.

FRDM-LS1-12A top view

Read more…

Switching to https with Let's Encrypt

As you may have noticed, the blog is now being served as a secure, encrypted page with the help of a fresh TLS certificate from Let's Encrypt.

Let's Encrypt

Ever since I first learned about this initiative supporting a more secure and privacy-respecting web, I wanted to use such a certificate for my blog. The immediate enthusiasm was slowed by the realization of the very short lifetime of the certificates and so the idea was left dormant for a while. With a validity of only three months, some sort of scripting infrastructre is needed to ensure that the certificates are renewed in a timely fashion and back then I didn't see an easy solution ready in a few minutes. Luckily enough, my web space provider Hostsharing eG integrated Let's Encrypt in a completely seamless fashion in the last weeks. All I needed to do was to tick the "Let's Encrypt Zertifikat" option in the HSAdmin web interface, specify the valid sub-domains and a few minutes later the website started serving the certificate.

Admittedly it took a little longer to find out why Firefox kept complaining about blocking mixed content on the TLS connection replacing the icons in the left hand panel by empty rectangles. Debugging the problem showed that the icons are in fact individual "characters" in an off-site font referenced by my chosen Nikola theme. Switching the template HTML to load the fonts also over https finished the transition.

Migrating a Laptop from Windows to Ubuntu

The old laptop of my wife was still running Windows Vista for a variety of reasons but not only did the support for that end but the laptop itself has become slow to a point that was unacceptable. Swapping in a SSD two years ago improved the performance back then to what one would expect but lately it spent hours with 100% usage of one of the cores in the Windows Update service with the only result of drowning the battery. I spent countless futile hours trying to reset that service and entering magic commands found in the Windows Support Centre and other semi respectable forums on the internet only to find out hours later that nothing had changed.

All in all, even though some functionality would not be available under GNU/Linux, there was no other way forward than to migrate it.

Ubuntu Gnome

Read more…

A Mathematician's Lament

Only recently I stumbled over A Mathematician's Lament by Paul Lockhart. More specifically over the freely available PDF linked from the Wikipedia entry.

Area of a triangle

Read more…

Cycling Gear Hubs and Their Efficiency

The number of electric bikes that I see on my cycling trips is growing steadily over the last few years so I started to read up on the used technologies and attributes of the different systems.

Using only derailleur gears on all of my bikes, I was surprised to see the variety and quality of hub gear boxes. For me this was something of the distant past linked to a specific two gear fold bike that my family owned back in the 70s. That one actually used backpedalling to switch between the two available gears. Spooky to even think about it nowadays.

Especially interesting is the CVP (continuously variable planetary) gear hub by Fallbrook Technologies Inc.

Nuvinci360

Read more…

Wake-on-lan

After upgrading my main desktop machine from Debian Jessie to Stretch, I wondered if my current solution to enable wake-on-lan on that machine could be replaced with something prepared in one of the upstream packages.

Wake-On-Lan

The old (but in my opinion still very elegant) solution consisted of a systemd template contained in /etc/systemd/system/wol@.service:

[Unit]
Description=Wake-on-LAN for %i
Requires=network.target
After=network.target

[Service]
ExecStart=/sbin/ethtool -s %i wol g
Type=oneshot

[Install]
WantedBy=multi-user.target

With this in place, all that is needed to enable wake-on-lan for eth0 is a simple:

root@deepthought:~# systemd enable wol@eth0.service

Read more…

GIT Large File Storage

Yesterday I wanted to push a git repository to GitHub to make the contents more visible. The content is a complete set of files together with a shell script to create a bootable SD card image for the SoCrates II SoC FPGA evaluation platform from Devboards. Next to the script itself, the repository thus contains a lot of binary blobs like the tarball of the root file system, the Linux kernel and FPGA sample bitstreams. Pushing such a repository to GitHub is not possible because of the current soft- and hard file size limits of 50 MiB and 100 MiB respectively.

git-lfs to the rescue!

git-lfs banner

Read more…

Migrating To Nextcloud

Although I was aware that the original author of ownCloud moved on to work on the Nextcloud fork, it never bothered me enough to check if I should migrate my ownCloud instance to the new software. With the recent reports on insecure ownCloud instances found by a scanner offered by the Nextcloud team, I took the time to investigate the situation.

Nextcloud Icon

Read more…

Trip Planning for Road Bikes

I wanted to write this post for some time, but only now having seen the pretty impressive improvements on the GNOME Maps application I was reminded of the topic and took the time to finally write it down.

The issue addressed in this topic is how to plan a "nice" route when travelling larger distances, say more than 40 kilometers, on a road bike. As this type of vehicle does not like going over gravel or other rough surfaces, a "nice" route should have paved surfaces all the time. This requirement is somewhat easy to fulfil when using routes calculated for cars. Unfortunately this guarantees a journey in heavy traffic let alone sections on "Bundesstrassen" where the speed difference to the passing cars is that high that driving a bicycle becomes very uneasy, let alone enjoyable.

outdooractive Route

Read more…

Videocalls for Cryptomessenger Signal

According to the Open Whisper Systems blog the Signal messenger (previously known as TextSecure under Android) now includes support for video calls. To use it, one needs to explicitly enable the beta feature. Of course both ends of a call need to do this.

Signal for Android Icon

Read more…