Category: Tips

Kali GPG Error the repository is not signed

Kali GPG Error

On April 28th Kali announced the rolling of a new signing key for the Kali repository. As a result, any existing installation will fail with the error GPG Error, the repository is not signed, when trying to update the repositories using the sudo apt update command:

Err:1 http://kali.download/kali kali-rolling InRelease
The following signatures couldn't be verified because the public key is not
available: NO_PUBKEY ED65462EC8D5E4C5
Warning: GPG error: http://kali.download/kali kali-rolling InRelease: The fol
lowing signatures couldn't be verified because the public key is not availabl
e: NO_PUBKEY ED65462EC8D5E4C5
Error: The repository 'http://http.kali.org/kali kali-rolling InRelease' is n
ot signed.
Notice: Updating from such a repository can't be done securely, and is theref
ore disabled by default.
Notice: See apt-secure(8) manpage for repository creation and user configurat
ion details.
Notice: Repository 'Kali Linux' changed its 'firmware component' value from
non-free' to 'non-free-firmware'
Notice: More information about this can be found online at: https://ww.kali.
org/blog/non-free-firmware-transition/

As stated on the official blog, to fix this issue, the new key should be manually installed using the following command:

sudo wget https://archive.kali.org/archive-keyring.gpg -O /usr/share/keyrings/kali-archive-keyring.gpg

This is the only required action. After that, sudo apt update will function as it did before.

Kali updating repositories

JetKVM – Control your serial devices over the network

Control your serial devices over the network

JetKVM is an open-source KVM over IP (Keyboard, Video, Mouse) solution designed for efficient remote management of computers, servers, and workstations. Originally launched as a Kickstarter project, I supported it and received my own device in early 2025. Like many renowned reviewers, I was impressed by the build quality of both the hardware and the software. However, this post is not just another review of the device. Instead, it will describe how you can further extend its functionality to manage even more devices—specifically, how to control your serial devices over a network.

Continue reading JetKVM – Control your serial devices over the network

Flash CC2531 using a Raspberry PI 4

CC2531USB
Many guides exist describing how to flash a CC2531 USB adapter using a Raspberry Pi instead of a CC debugger. The problem with almost all of those guides is that they are outdated and don’t work on newer devices (specifically with 64 bit architecture). Most of the times the issues have to do with outdated version of wiring PI, or the precompiled for 32 bit devices cc_* binaries (cc_chipid, cc_read, cc_write). In this guide you will learn how to flash CC2531 using a Raspberry PI 4 or any other device with 64 bit architecture OS.

Continue reading Flash CC2531 using a Raspberry PI 4

Raspberry PI 4, 400 and CM custom MAC Address

Today I read this official document (published on September of 2022) which describes how to change the MAC Address of Raspberry PI Devices. Interestingly it describes a different method for Raspberry Pi 4, 400 and CM 4 by editing the EEPROM configuration, using the following command:

sudo -E rpi-eeprom-config --edit

In the configuration file append a new line with the required MAC Address as follows:

MAC_ADDRESS=aa:bb:cc:dd:ee:ff

Save the new configuration (Use Ctrl + X to stop editing, Y to overwrite current file and ENTER to confirm). Upon saving the following message appears:

Pi4_mac_change

Finally, reboot your device in order to apply the new MAC Address. Warning If the device gets IP from a DHCP server, then most probably after the reboot it will be assigned with a new IP address.

This is a different (and simpler) technique from the one which I described in a previous post (which works for all models)