[RaspberryPi] Fix Missing Bluetooth Audio Sink

If you notice “error: a2dp-source profile connect failed for protocol not available“, probably in the log or via systemctl

sudo cat /var/log/syslog | grep -i protocol
sudo systemctl status bluetooth

open the bluealsa.service file

sudo nano /lib/systemd/system/bluealsa.service

and append the a2dp-sink:

ExecStart=/usr/bin/bluealsa --profile=a2dp-sink

Now reboot. Check with

sudo bluetoothctl show

Using Proxmox Host as HTPC

In February this year I built a tiny second Proxmox Host with the ASRock DeskMini A300 and the following parts. I chose an AMD Ryzen 5 3400G (with integrated APU) CPU.
As HTPC I always used a RaspberryPi 3 running LibreElec (Kodi) with the Jellyfin for Kodi Plugin to access my media. But the the Raspberry reached its limits when it comes to 4k content or 10bit Audio lines. So why not use the DeskMini A300 as Proxmox Host and also as HTPC? It has enough power to play all types of media and even some steam games would run on it.
So a few things had to be done.

  1. Install a Desktop Environment & Login Manager on the Host
  2. Add a user
  3. Install some basic software (Firefox, VLC, JUK…)
  4. Set up YouTube Leanback
  5. Consuming Jellyfin media
  6. Set up Plasma Activities for each service
  7. Controlling media with KDE Connect

Of course it’s not recommended to install more than necessary on the host itself, so this shouldn’t be done on a productive Proxmox-System.
Proxmox Wiki says: “Installing additional packages could lead to a hardly upgradeable system and is not supported from the Proxmox support team and therefore only for expert use.”
Because I’m using my Proxmox Host just for my Homelab (pi-hole, nextcloud, reverseproxy etc.) I’ll take the risk.
When using a host with dedicated graphics card, you could also create a VM and pass it through, so you don’t have to mess around on the host like I have to do.

1. Install a Desktop Environment & Login Manager

There is a Proxmox Wiki describing it: https://pve.proxmox.com/wiki/Developer_Workstations_with_Proxmox_VE_and_X11
As DE I took KDE Plasma, but just the plain desktop. See here for all three options: https://wiki.debian.org/KDE

KDE (Full release of workspace, applications and framework)kde-full packageThe standard/upstream release
KDE (A common set of packages for a smaller, more flexible KDE environment compared to kde-full)kde-standard packageDebian’s selection of common KDE packages
KDE Plasma Desktopkde-plasma-desktop packageThis is a minimalist Plasma desktop
(You have to install all end-user applications later).

This was my command:

apt-get update && apt-get dist-upgrade
apt-get install kde-plasma-desktop lightdm

2. Add a user

As simple as always. Edit the visudo for root permissions and

adduser newusername

add the following line to the end

newusername ALL=(ALL:ALL) ALL

Afterwards you have to start the login manager

systemctl start lightdm

Now you’re ready to login.

3. Install software

As I took the plain KDE Plasma Desktop, there is nearly no other software besides the necessary programs for the DE.
I installed just a few things on top:

apt install konsole vlc firefox-esr tldr neofetch gwenview juk kcalc ncmpcpp kodi

4. Set up YouTube Leanback

In September 2019 YouTube announced to end Youtube Leanback TV (a web interface which could simple be opened in any browser via youtube.com/tv).
But it still exists and can be used with a simple workaround I found on reddit. Simple install the Firefox Addon User Agent Switcher and add the following line in userAgent:

Mozilla/5.0 (SMART-TV; Linux; Tizen AppleWebkit/605.1.15 (KHTML, like Gecko)

When browsing to youtube.com/tv you should get the Leanback interface in which you can easily navigate via keyboard. Now just press F11 to go in full screen mode.

Of course you can connect the YouTube App of your Smartphone and just cast videos to it just like with a Chromecast or the native YouTube Smart TV app. I would recommend using the Vanced App if you want to see less ads.

5. Jellyfin

I tried two ways consuming media of my Jellyfin server (which is running in an LXC on the same Host) and both work fine.
First I used Kodi plus the Jellyfin for Kodi plugin. If you are already using Kodi for other stuff, integrating your Jellyfin content here is probably the best.
As second option, and what I’m using still today, is simple the Jellyfin Web Version via browser in full screen mode. Just activate the TV modus in the Jellyfin settings. There are some minor bugs when navigating via keyboard but most of the time it runs perfect. But because Firefox is still not playing MKV files (see bug 1422891) I had to install Chromium for proper use of Jellyfin.

apt install chromium chromium-l10n

Just enter the full screen mode with F11 and it looks pretty well on your TV.

6. Plasma Activities

When using KDE Plasma you can simple create Activities (click here to see how to create an activity) for each of your full screen running application and easily switch between them. In my case I created three Acitivites, one for YouTube Leanback, one for Kodi and one for Jellyfin. A of course there is the Standard Activity, which is just my normal desktop for viewing other content like photos or playing a Steam game. This way I can switch through all my full screen applications via Super + Tab (or backwards with Super + Shift + Tab).

7. KDE Connect

If you dont wan’t to use the keyboard the whole time to control your media on your HTPC, you should try KDEConnect on your Smartphone. You’ll get the app from the F-Droid Store: KDE Connect.
Next just install the application on your host with:

apt install kdeconnect

and pair the two devices. By default whenever media is played on your HTPC the app will now present you an interface to control it (with play, pause, next etc.). Also you are able to control the mouse via touch on your Smartphone. And there are some other functions you should check out as well.

I’m really enjoying this new setup. It’s much more powerful, flexible and easier to handle than my old RaspberryPi 3. I will keep an eye on whether there will be problems with a system update in the future.

[Wireguard] Set up Wireguard using PiVPN inside LXC

Recently I had to setup a new Proxmox host and also had to setup a VPN to access the network of the host. This time I gave PiVPN a try, since it recently added support for Wireguard.
So first I installed Wireguard on the host like here (without adding the TUN device to the containers config), set up a new unprivileged container running debian buster, set up port forwarding in the router, installed curl followed by the one liner for PiVPN.

apt install curl
curl -L https://install.pivpn.io | bash

And that was almost it. Now just add a device and use the QR-Code the use it on Android.

pivpn -a
pivpn -qr

PiVPN delivers what it promises! That was super easy to setup.

[ZFS] diff – what changed between ZFS snapshots

The diff command tells you what files were changed/added/deleted between snapshots.

#list snapshots of a dataset
zfs list -rt snapshot | grep zpool/dataset
#choose two snapshots and use the diff command
zfs diff -FH zpool/dataset@zfs-auto-snap_monthly-2020-03-01-0552 zpool/dataset@zfs-auto-snap_monthly-2020-04-01-0452

The diff command can also show the difference between a snapshot and a current dataset.

zfs diff -FH zpool/dataset@zfs-auto-snap_monthly-2020-03-01-0552 zpool/dataset

The first column indicates the type of change:

-       The path has been removed
+       The path has been created
M       The path has been modified
R       The path has been renamed

The second column indicates the file type, similar to ls. For further information have a look into the zfs man page.

[RaspberryPi] Forwarding USB Audio Input to HifiBerry AMP2

For music playback at home I have built my own Bluetooth Speaker. It’s RaspberryPi 3, on top a HifiBerry AMP2, and they are powering two B&W DM601.
I have used this script to setup bluetooth and configure the audio settings.
Because bluetooth is the only way to pass audio to the raspberry (besides running music on the raspberry itself, e.g. via MPD/MPC), I was thinking of a way passing audio via chinch cable. I grabbed an old USB Soundcard I had laying around and connected it to the raspberry. Now I had to forward the USB Soundcard Audio Input to the HifiBerry AMP2. I found a way using PulseAudio for this. Got it from here.

#find input device (my USB Soundcard)
pactl list sources
#find output device (my HifiBerry AMP2)
pactl list sinks
#set loopback
pactl load-module module-loopback source=src_name sink=sink_name

But most USB Soundcards only have Mono-Audio-In and the there a often annoying noises through the input… So this way really no joy and I will continue using bluetooth.


HMDIHigh Definition Multimedia Interface
HDMI-ARCAudio Return Channel
HDMI-CECConsumer Electronics Control

Andere Bezeichungen bei Herstellern:
Philips -> EasyLink
LG -> Simplelink
Samsung -> Anynet+
Sony -> BRAVIA Sync

[ABAP] SE80 Shortcuts

Meine meist verwendeten Workbench Shortcuts:

Strg DZeile verdoppeln
Strg JIn Kommentaren -> 1 Buchstaben groß
Strg ISuchen
Strg Shift ISuchen aufwärts (startet beim tippen)
Strg KText groß/klein switchen
Strg Shift SCoding in Datei speichern
Strg Shift LGanze Zeile löschen
Strg Shift XGanze Zeile löschen und einrücken
Ctrl /Jump to the “command field” where we enter t-codes

[SAPUI5] Formatting numbers

a few examples: https://github.com/brooklynb7/HTML5/blob/master/sapui5-dist-static/test-resources/sap/ca/ui/demokit/explored/views/type/number.view.xml

number="{ model : 'income', path : 'Cost', type: 'sap.ui.model.type.Integer', formatOptions: {groupingEnabled: true} }"
numberUnit="EUR" />

[SAPUI5] Deploying the ui5 sample app on debian

I’m deploying the openui5-sample-app to an Linux Container running Debian Buster. First update the packages and install nodejs.

apt update && apt upgrade -y
apt install curl -y
curl -sL https://deb.nodesource.com/setup_12.x | bash -
apt install nodejs -y
nodejs --version

Install PM2 (process manager to manage Node.js applications) and the UI5 Tooling

npm install pm2 -g
npm install --global @ui5/cli

Now clone the openui5-sample-app and build it

apt install git
git clone https://github.com/SAP/openui5-sample-app.git
cd openui5-sample-app/
ui5 build -a
cd ..

Run your project on port 8000. With “startup” it will automatically create a systemd script.

pm2 serve openui5-sample-app/dist/ 8000
pm2 startup
pm2 save
systemctl start pm2-root
systemctl status pm2-root