Searching for the KY-012 active piezo buzzer module, you will find a lot of articles on how to connect it with a Raspberry Pi. Unfortunately, some of them are wrong and could in the worst case damage your Raspberry Pi. This article explains why this is the case and what would be a better alternative.

Recently I had a bricked Netgear switch in my hands, which could get fixed via onboard UART interface. This is a quick how-to.

ODROID boards are perfect for building custom Linux based firewall solutions. A friend of mine recently asked me for instructions on how to do that. So here they are.

There are many articles on the internet on how to generate a TLS certficate with the Subject Alternative Name (SAN) extension, but most of them won't work anymore. So here is another one, which hopefully works.

The El Torito Bootable CD Specification was introduced in the 90's to make it possible to boot a system from a CD. This specification is used till today for bootable ISO images. There are different ways to embed disk images into El Torito ISO images. One way is called hard disk emulation. With this the bootable disk image comes with a DOS/MBR boot record and can be booted by the BIOS/UEFI directly. Unfortunately if you want to boot such an ISO from an USB stick, that won't work out of the box, you need to extract the disk image from the ISO first. This article is about how you can do that easily under Linux.