Iksas

Notes on the MS2109 HDMI capture card

I tested the capture card with obs-studio and the latest version of Debian.

OS compatibility

Video

Video input works with all operating systems.

Disassembling ARM binaries

The attached script uses Capstone to disassemble small ARM binaries, including Raspberry Pi kernel images.

It only displays assembly opcodes, and doesn't differentiate between code and data sections.

Arguments

Buster >> Bullseye - Remote upgrade

These instructions can be used to upgrade Raspberry Pi OS from Buster to Bullseye with only an SSH connection (no physical access). Some addidional steps are performed to make sure that the Pi automatically joins the WiFi network after upgrading. This is necessary if the Pi is located in a remote or hard to reach location.

Especially on older Pis, the upgrade will take several hours, so plan accordingly.

If you have physical access to the Pi, consider making a backup of the SD card with the SD Card Copier utility (red berry menu in the top left >> Accessories >> SD Card Copier). If the SD Card Copier is not in the menu, you can install it with sudo apt install piclone.

Pi-hole blocklists

The following file contains blocklists I use with my Pi-hole installations.

It blocks with minimal false positives:

ads / spam / telemetry / tracking
malware
phishing and fraudulent websites
torrents

Moodle 4.0 custom CSS

The following CSS can be used make the layout of Moodle 4.0 more compact.

Use it with a browser extension that permits the application of user-defined CSS, for example Stylus (on Firefox or Chrome).

My Firefox user.js

Type about:profiles into the URL bar to display the profile folder path.

Copy the user.js file to the default profile's root folder.

After restarting Firefox, about:config can be used to check if the settings have been applied correctly.

git cheat sheet

Search the reflog for info about a commit (only works if the relevant info hasn't been garbage-collected):

git reflog --no-abbrev | grep <HASH>

List the number of lines in each file:

git ls-files | xargs wc -l

Fixing `wg-quick` on macOS

On some macOS setups, wg-quick up does not work correctly if the Wireguard configuration includes a DNS server address.

When this error occurs, wg-quick up exits with the following lines, and the Wireguard tunnel will not work:

$ sudo wg-quick up wg0
...
[#] rm -f /var/run/wireguard/utun3.sock
[#] rm -f /var/run/wireguard/wg0.name

Fixing systemd sandboxing errors

Crash with `status=31/SYS`

user@ansible-test:~ $ journalctl -u mongod.service | tail
[...]
Aug 08 17:29:42 ansible-test systemd[1]: Started mongod.service - MongoDB Database Server.
Aug 08 17:29:43 ansible-test systemd[1]: mongod.service: Main process exited, code=killed, status=31/SYS
Aug 08 17:29:43 ansible-test systemd[1]: mongod.service: Failed with result 'signal'.

	import argparse

	...

	if __name__ == "__main__":
	# parse CLI arguments
	parser = argparse.ArgumentParser(description="Search popular Hacker News posts")
	parser.add_argument('-u', '--update', default=False, help='update the database', action='store_true', dest='update')
	parser.add_argument('-d', '--domain', default=False, help='search for posts from a domain', action='store_true', dest='domain')
	parser.add_argument('query', nargs='?', help='the search query')