Archive for the ‘Webtechnology’ Category

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Running Raspberry Pi OS on a RPI Zero without SD card

Saturday, January 2nd, 2021

I’ve blogged before about how to boot a Raspberry Pi Zero over USB without an SD card, just powering it with an USB cable in the middle USB connector, and connecting at the same time.

This Christmas I tried it with a new Buster version and a trusty old Raspberry Pi Zero and following the tutorial it’s still running fine with the latest Raspberry Pi OS 2020-12-02-raspios-buster-armhf-lite.img.

Time for some improvements. Updating and upgrading was always possible, but not always successful: you could easily run into disk-space problems.

Default images are shipped/downloaded as small as possible and the default action of booting a Pi with a new image is resizing the root partition to claim all available space on the SD card.

We’re mounting over NFS and of course the resizing did not happen in our case. Luckily, otherwise your guest OS would end up with no space and the Pi would have a partition size of 1GB (or so).

But for upgrades we need more space than the default.

How to increase the image size of an mounted image over NFS?

The image I have downloaded is `2020-12-02-raspios-buster-armhf-lite.zip`, and we have to follow 4 simple steps.

Step 1: unpack it:

unzip 2020-12-02-raspios-buster-armhf-lite.zip 2020-12-02-raspios-buster-armhf-lite.img

Step 2: resize raw image:

Then use qemu-img (QEMU disk image utility) to resize the raw image.

sudo qemu-img resize 2020-12-02-raspios-buster-armhf-lite.img 3G

Here we resize it to 3G, that must be enough to install some extra programs, and download and install updates.

Step 3: set it up as loop device:

sudo losetup -P /dev/loop101 2020-12-02-raspios-buster-armhf-lite.img

These day I set it up as loop101 instead of loop0 as I did in the blogpost of 2018 to avoid conflicting loop devices. Snaps are also installed as loop devices.

Step 4: resize root partition

start gparted with the loop device to resize the root partition.

sudo gparted /dev/loop101

Normally gparted never shows loop devices, but it does when you explicitly start with a loop device.

Then simply push the slider to resize the image, and apply the changes and you’ve gained 900MB of disk-space.

More than enough to do updates and upgrades for years to come.

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Text with pattern the new way

Sunday, October 4th, 2020

In the past the only way to to get colored text, like from an image or gradient was to use SVG.

Nowadays pure CSS is enough.

Although a prefix with -webkit- is still needed for Safari and Blink browsers.

.post-2027 h1{
background-image: linear-gradient(
90deg,
#7383c1 0%,
#bed876 50%,
#e0b384 100%
);
background-clip: text;
-webkit-background-clip: text;
color: transparent;
width:max-content;
}
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Why the upgrade from Ubuntu 18.04 LTS to Ubuntu 20.04 LTS is not available yet.

Wednesday, September 9th, 2020

Linux users of the Ubuntu 18.04 LTS (Long Term Support) are still waiting to upgrade their systems to 20.04. Normally at around the time the first point release of the new LTS distribution is released.

What is a point release?

These point releases include support for new hardware as well as rolling up all the updates published in that series to date. So a fresh install of a point release will work on newer hardware and will also not require a big download of additional updates. These include security updates and corrections for other high-impact bugs, with a focus on maintaining stability and compatibility with Ubuntu 20.04 LTS.

And 20.04.1 was released on August 6. But the problem is: not all flaws have been ironed out yet in 20.04.1. So at the moment you can’t be confident to get a smooth upgrade from 18.04 LTS. That’s why the upgrade is not yet available. Yes you can get a smooth install, but not a smooth upgrade.

Upgrade blocking bugs for 20.04

There are 2 blocking issues at the moment, and they must be solved first:

  1. eoan to focal upgrade hangs when lvm snapshot is present (bug 1876506) resolved
  2. grub-pc upgrade support (bug 1891680)

Here you can track the release status.

If you wanna take the risk, you can always force a upgrade with:

do-release-upgrade -d
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Getting the date right in Javascript in your language of choice

Thursday, August 20th, 2020

The Internationalization API provides language number formatting, string comparison, and date/time formatting in Javascript. It’s a global object.

Intl.DateTimeFormat('en-GB',
{
day: '2-digit',
hour: '2-digit',
minute: '2-digit',
second: '2-digit',
weekday: 'long',
era: 'long',
year: 'numeric' ,
month: 'long',
timeZoneName: 'long',
hour12: false
}).format()

What is the time today?

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Macro Photography with the Raspberry Pi HQ camera and reverse mounted lens III

Saturday, June 6th, 2020

Another try with some extra lighting, and post-processing with Darktable. See my earlier posts about photographing with the Raspberry Pi HQ Camera: part I and part II.

This time I used a special build of raspistill that offers a Field of Merit function to assist focusing. The Raspberry Pi Forum is full of helpful people and is very informative.

Fruit-fly taken with a Raspberry Pi HQ Camera and a reverse mounted Pentax 35mm lens

Fruitflies are the really minuscule flies that hang around you garbage bin, or home plants in the windowsill.

Not sure what the yellow blob is, maybe I caught the fly eating a piece of banana.

 

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Install Firefox Android on Android AOSP

Saturday, June 6th, 2020

A small update on an older post Install Android browsers without Google Play because the download link on Mozilla’s pages has changed.

https://download.mozilla.org/?product=fennec-latest&os=android&lang=multi (direct download)

Also F-droid is highly recommended for free and open-source software.

F-Droid is a community-maintained software repository for Android, similar to the Google Play store. The main repository, hosted by the project, contains only free/libre apps. Applications can be browsed, downloaded and installed from the F-Droid website or client app without the need to register for an account. “Anti-Features” such as advertising, user tracking, or dependence on nonfree software are flagged in app descriptions.

https://en.wikipedia.org/wiki/F-Droid