Controlling LEDs on Alpine Linux using the command line

We have developed an embedded Raspberry Pi Compute Module carrier board for industrial use: the PCCB. As you can see, there are three (directly) user programmable LEDs on the PCCB: USER / INFO / ACT. These are defined in the device tree. For example, we can define the following in our device tree overlay: //LEDs…

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Booting Alpine Linux on the Raspberry Pi Compute Module

In our project for a client we are using the Raspberry Pi Compute Module, along with a custom compute module carrier board (called the PCCB – Pi Control Carrier Board) which provides RS485, CAN, RS232, LAN, USB and a step-down for input voltages of 6 – 24 V. (If you are interested in customized hardware…

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Alpine 3.9.0 initramfs init changes

Alpine 3.9.0 ships a new version of the init script in it’s initramfs. left: Alpine 3.9.0, right: Alpine 3.8.2 There are a number of interesting changes: better and earlier networking support for the boot process, with an additional kernel parameter for cmdline.txt: BOOTIF, allowing you to specify the device interface you want to use for…

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Debugging the Alpine boot process

As discussed in my previous post, Alpine Linux goes through several stages when it boots. Just after mounting the boot media, and scanning it for apkovl’s (with nlplug-findfs), there is an option for you to get a console, by setting $SINGLEMODE to yes. Setting SINGLEMODE to yes is easy, you simply add the word “single”…

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Alpine boot process on the Raspberry Pi

Today we will have a look at the Alpine Linux boot process on a Raspberry Pi in some detail. The picture shows the contents of a „virgin“ SD card with the Alpine image, which has not been booted yet. This picture shows the contents of the boot folder. Initial boot Stages on the Raspberry Pi…

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nlplug-findfs documentation

nlplugfs-findfs usage: %s [options] DEVICE options: -a OUTFILE add paths to found apkovls to OUTFILE -b OUTFILE add found boot repositories to OUTFILE -c CRYPTDEVICE run cryptsetup luksOpen when CRYPTDEVICE is found -h show this help -H HEADERDEVICE use HEADERDEVICE as the LUKS header -k CRYPTKEY path to keyfile -m CRYPTNAME use CRYPTNAME name for…

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Crystal & Alpine on the Raspberry Pi

Bringing together two interesting technologies: Alpine Linux – a small-size and security oriented Linux distribution Crystal – a compiled language with a nice syntax (similar to Ruby) on the Raspberry Pi (armhf / ARMv6, which would also support the Pi Zero W) is not possible currently, as of 21.12.2018. There is no (at least no…

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Alpine Linux first steps

Here’s a short primer to Alpine Linux, specifically for the Raspberry Pi platform Why Alpine Linux? it’s small it can be installed by copying files on the FAT partition of the SD it can run from RAM, the filesystem will remain read-only (persisting changes is of course possible) this is very good for embedded systems…

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