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Brainwaves Linux

PinePhone Daily Cron Fixed

I needed to run a daily cron job on my PinePhone, but that turned out to be trickier than expected. How can you schedule a job to be run in the morning, when the phone is most likely asleep (suspended) at that time?

My solution (workaround?) was to have the cron job run every 10 minutes, checking if the job was already executed today and if not, run the actual job command. This check is pretty cheap and I don’t need to wake the phone up to run my job. All I need is to get the job executed “today, whenever you have the time”.

The Cron Limiter tool (crolim for short) is available in my snippets repository.

With this tool, the crontab is as easy as: */10 * * * * crolim podget. Now my daily podcasts can be downloaded daily, when the phone is awake.


Brainwaves Linux Open source

PinePhone Printing on a Thermal Receipt Printer

I like using PinePhone as a general purpose computer for various tasks and purposes, such as a dedicated alarm clock, trying out networking software (I have several of them), etc. This time I tried attaching a POS Printer, creating a print server.

Linux is great when it comes to printers support, thanks to CUPS. It usually just works. For the POS Printer I needed to install additional drivers, but luckily there are some generic ones available, covering most of the 58mm / 80mm thermal printers (they share the same ESC/POS protocol, making them widely compatible).

Initially I wanted to use the official vendor-supplied printer drivers for Linux ARM, but there are several ARM architectures and this wasn’t the right one. Therefore I used these CUPS drivers instead: github.com/klirichek/zj-58. And since this is open source, I was able to compile them for the PinePhone’s ARM architecture and get it working.

Adding a printer can be done through the CUPS web interface running on localhost:631, where you can add the printer connected over USB. You can also connect a printer over serial or Bluetooth, all you need is a special connection URL: serial:/dev/ttyXXX or bluetooth://123456789a/ where you specify the serial file or the device address.

Once the printer is added, you can use all the lp* commands to manage your print jobs, such as lpoptions to configure the printer defaults, or lp tux.png to print out an image on a thermal printer!


Brainwaves Raspberry Pi

Kodi on Raspberry Pi 3 running Arch Linux ARM

When setting up Kodi under Arch Linux ARM running on Raspberry Pi 3, I encountered this error, which crashed the graphical environment right from the start:

[drm:vc4_bo_create [vc4]] ERROR Failed to allocate from CMA:

After some searching, I ran into an issue thread, where it was advised to increase the CMA memory (as a workaround that seems to just be the actual fix). You need to add ‘cma=256M’ to the kernel boot parameters. But how do you do that?

# Run as root...

# dependencies
pacman -S uboot-tools

# modify the kernel boot parameters
cd /boot
vim boot.txt # append cma=256M to the line with boot params

Before this fix, I had only 64 MB of CMA. This wasn’t enough. To check that this worked:

if the cma parameter is present and /proc/meminfo

cat /proc/cmdline
# should contain cma=256M

cat /proc/meminfo | grep Cma
# should say CmaTotal: 262144 kB

Now Kodi finally starts!

…though there are still some problems with the graphics driver (video doesn’t play, random switching to the console and back).

As it turns out, using the AArch64 version of Arch Linux ARM for Kodi is not the best option. Switching to the ARMv7 version helped a lot, everything worked from the start.


Awesome Hardware Linux

Orange Pi Zero running in QEMU

I needed a way to run an Orange Pi Zero SD-Card image of Armbian as a virtual machine. And this is actually possible with QEMU!

This is the command I used:

qemu-system-arm \
-M orangepi-pc -m 1024 -cpu cortex-a7 -dtb boot/dtb/sun8i-h3-orangepi-pc.dtb \
-kernel boot/vmlinuz-5.4.45-sunxi -initrd boot/initrd.img-5.4.45-sunxi \
-append 'earlyprintk loglevel=8 earlycon=uart8250,mmio32,0x1c28000,115200n8 console=ttyS0 root=/dev/mmcblk0p1' \
-nographic -serial stdio -monitor none \
-drive file=Armbian_20.05.3_Orangepizero_buster_current_5.4.45.img,format=raw,if=none,id=d1 \
-device sd-card,drive=d1 \
-nic user,model=allwinner-sun8i-emac,hostfwd=tcp::50022-:22

Original source: https://forum.armbian.com/topic/7547-run-armbian-into-qemu/?tab=comments#comment-86797

You need to get the contents of the /boot directory from the SD Card image so that you can start booting it. I just used scp to copy it from a running Orange Pi Zero to my main machine. The command above doesn’t actually run an Orange Pi Zero board, it runs an Orange Pi PC, though this is almost the same thing. At least the CPU is the same (note: Allwinner H2+ and H3 are binary compatible). But it has more memory!

Why run Armbian in QEMU?

I wanted to compile an application written in Rust. The problem was that installing it the official way through rustup (or more precisely rustup-init) resulted in an error:

info: installing component 'cargo'
info: Defaulting to 139.4 MiB unpack ram
thread 'main' panicked at 'RUSTUP_UNPACK_RAM must be larger than 220000000', src/dist/component/package.rs:200:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'main' panicked at 'No process instance', src/currentprocess.rs:126:17

The newer versions of rust required more memory than the Orange Pi Zero had! Mine had 256 MB (since I thought I’d take this as a challenge instead of going with the 512 MB version). Rustup needed at least 220 MB on its own.

Alternatively I could get some cross-compilation toolchain. But that seemed even harder; I couldn’t find anything usable.



Serial Connection to Orange Pi 4

I thought I’d use my trusty CP2102 USB-UART adapter. But as it turns out, it only works up to 1 Mbps, while the Orange Pi 4 is running at 1500000 bauds. Oops.

My other attempt was to try the Raspberry Pi‘s serial port, but that also didn’t work. The data coming in was also just a random garbage.

I tried using a random Arduino‘s on board serial module CH340 (while having Reset hooked up to GND so that it bypasses the Atmel chip) but that for some reason didn’t produce any data on the high baud rate. Even though based on the specification of the chip the baud rate should be supported.

My next attempt was with an ESP32 dev board, hooking it up similarly to an Arduino. No luck, turns out there is again the CP2102 chip. There was some output from the Orange Pi 4, but again it was garbage since it can’t keep up at this speed.

Finally I found a lonely DAPlink module that is specifically designed for ARM programming. Among other things it has a UART with 3.3V TTL levels. And bingo, this one was fast enough to finally read the Orange Pi 4’s debug UART port.


Awesome Linux Open source PinePhone Projects

Mouse in a Pipe

Have you ever wanted to control your notebook directly from your desktop? How about controlling your phone? Wouldn’t it be better to type that chat message using a real keyboard? I wanted the same thing, so I wrote an app for that!

More precisely I created a tool that enables you to redirect mouse and keyboard events from one device to another. It’s like you reconnected your mouse and keyboard, but without the physical effort! All of this happens on a very low level (through the kernel) so this works seamlessly with any application you want to control. All you need is a Linux OS on both of the devices.

Repository: https://github.com/Dejvino/mouse-piped

One more interesting point is that the input events are pushed through a pipe, which is a generic way of transferring data among processes in Unix-based operating systems. It is up to you how you decide to transfer the data. Though most likely it will happen via SSH. You can easily generate input events on your main computer and then pipe them through SSH to your secondary computer (or a phone) and control it that way. Or you might decide to create a TCP connection and pass the data through that. That’s up to you!

And you know what else is this useful for? That’s right, you can finally play OpenTTD on a PinePhone with the full comfort of a mouse and keyboard!


Linux Open source PicoPosts PinePhone Projects

Arch Linux ARM Installer for PinePhone

I started building an automated Arch Linux ARM installation and customization set of scripts to be used for the PinePhone. The aim is to make the process easier while still being able to customize every aspect of the OS.

Repository URL: https://github.com/Dejvino/pinephone-arch-install

Arch Linux ARM running LXDE, Firefox and Onboard keyboard.

Arch Linux ARM was the best OS for PinePhone I’ve seen so far. It might be due to personal preference, but I just love how you have the full power of Arch on your mobile phone.

And if Arch is not your thing, at least you can learn what are the steps required for bringing a Linux OS into a PinePhone.


Linux PinePhone

Errors During PinePhone Install

I learned a lot about hardware and operating systems since I received my PinePhone. A lot of times it was during error investigation. With a small chance that this information might get picked up by another PinePhone enthusiast, I’ll post the error messages and my solutions here.

RTL firmware not found

Bluetooth firmware on my Arch Linux ARM was missing, it is a non-free firmware so it is not included by default.

Feb 23 19:21:58 alarm kernel: bluetooth hci0: Direct firmware load for rtl_bt/rtl8723cs_xx_fw.bin failed with error -2
Feb 23 19:21:58 alarm kernel: Bluetooth: hci0: RTL: firmware file rtl_bt/rtl8723cs_xx_fw.bin not found

With this I just went over to my postmarketOS SD Card image and copied the corresponding files from /lib/firmware/rtl_bt/ over SSH

scp lib/firmware/rtl_bt/rtl8723cs_xx_fw.bin root@pinephone_ip_address:/lib/firmware/rtl_bt/
scp lib/firmware/rtl_bt/rtl8723cs_xx_config-pinebook.bin root@pinephone_ip_address:/lib/firmware/rtl_bt/rtl8723cs_xx_config-pinephone.bin # notice the rename

systemd-binfmt Failed

I was getting a lot of binfmt-related errors like the ones in bold below. And if there is one thing you don’t want to see it is a red FAILED log line during boot process.

Feb 23 19:36:10 alarm systemd[1]: Mounted Temporary Directory (/tmp).
Feb 23 19:36:10 alarm systemd[1]: Started Create list of static device nodes for the current kernel.
Feb 23 19:36:10 alarm systemd[1]: systemd-binfmt.service: Main process exited, code=exited, status=1/FAILURE
Feb 23 19:36:10 alarm systemd[1]: systemd-binfmt.service: Failed with result 'exit-code'.
Feb 23 19:36:10 alarm systemd[1]: Failed to start Set Up Additional Binary Formats.
Feb 23 19:36:10 alarm systemd[1]: Started Load Kernel Modules.
Feb 23 19:36:10 alarm systemd-binfmt[267]: Failed to add binary format: No such file or directory
Feb 23 19:36:13 alarm systemd[1]: Starting Load/Save RF Kill Switch Status…
Feb 23 19:36:13 alarm systemd-binfmt[385]: Failed to add binary format: No such file or directory
Feb 23 19:36:13 alarm systemd[1]: Condition check resulted in Create System Users being skipped.
Feb 23 19:36:13 alarm systemd[1]: systemd-binfmt.service: Main process exited, code=exited, status=1/FAILURE
Feb 23 19:36:13 alarm systemd[1]: systemd-binfmt.service: Failed with result 'exit-code'.
Feb 23 19:36:13 alarm systemd[1]: Failed to start Set Up Additional Binary Formats.
Feb 23 19:36:13 alarm systemd[1]: Started Load/Save RF Kill Switch Status.

So I went to investigate the service’s config files, seeing the “Failed to add binary format: No such file or directory” error. There are several directories that binfmt is looking for its config files. As it turns out all of them were empty apart from one. I found out that after installing mono it registered itself with binfmt. Not sure why, but I certainly don’t need it, so the solution is simple.

rm /usr/lib/binfmt.d/mono.conf 


Broken Battery In ACPI

Multiple components make use of the ACPI and all of them report a dead battery. E.g. battery applet or laptop-mode service:

Feb 23 19:22:05 alarm laptop-mode[1653]: Failed to re-set power saving mode for wireless card
Feb 23 19:22:05 alarm laptop-mode[1700]: WARNING: Battery does not report a capacity. Minimum battery
Feb 23 19:22:05 alarm laptop-mode[1701]: charge checking does not work without a design capacity.
Feb 23 19:22:05 alarm laptop-mode[1702]: WARNING: Battery does not report a design capacity. Auto hibernation
Feb 23 19:22:05 alarm laptop-mode[1703]: does not work without a design capacity.
Feb 23 19:22:05 alarm laptop-mode[1704]: You seem to have a broken battery
Feb 23 19:22:05 alarm laptop-mode[1705]: Cannot determine design_capacity_warning
Feb 23 19:22:05 alarm laptop-mode[1706]: Disabling hibernation
Feb 23 19:22:05 alarm laptop-mode[1707]: Failed to determine battery charge. Battery charge units are not in
Feb 23 19:22:05 alarm laptop-mode[1708]: mWh, uWh, mAh or uAh.
Feb 23 19:22:05 alarm laptop-mode[1711]: enabled, active

This is not the case since the battery is actually fine, it just doesn’t work with ACPI:

# cat /sys/class/power_supply/axp20x-battery/uevent 

Seems the kernel I’m using doesn’t have it enabled, as you can see here:

#  ls -l /usr/lib/modules/$(uname -r)/kernel/drivers/acpi
ls: cannot access '/usr/lib/modules/5.6.0-rc1-00239-geb93b104bbccb/kernel/drivers/acpi': No such file or directory


Linux Open source PinePhone

PinePhone Status Review 2020-02-22

I’ve spent a bit of time with my new Linux toy, PINE64 PinePhone. This is a smartphone built on top of components that are supported well by the mainline Linux kernel. So in theory it should be a piece of cake to get installed. Is it?

Various Gotchas

Let’s start with a few gotchas that somewhat surprised me.

WiFi needs a battery

The WiFi / GSM modem needs a battery to be connected in order to operate. Otherwise it won’t even appear as an available device. You could spend a lot of time trying to connect to the WiFi like this. In vain.

Power Hungry

The phone is really hungry for power and often it is not enough to connect it to a PC. The battery will discharge even when connected via a USB cable, unless the power source is strong enough. Running on 0.5A (2.5W) is not enough. It generally takes around 1.4A (7W) when running a full featured OS and it will drop to 0% eventually.


You never appreciate it enough until you lose it. Having a shell in your phone is great. Though you can’t really use it, since there is no keyboard available. This one is somewhat obvious, but it is a big hurdle when trying out various systems. You can install some virtual keyboard, but it won’t have all the keys you need and it doesn’t work in every environment. Not reliably at least. Your best bet is to get an SSH connection going as a workaround. Hardware keyboards are not supported / don’t exist right now.

Operating Systems

I’ve tried out multiple systems and environments, here are a few thoughts about them.


I’d say this is the best OS out there right now. At least in terms of having a solid PinePhone support, configurability and a reasonable Linux distribution underneath. It has a dedicated PinePhone wiki page. You have a choice of multiple UI environments (including phosh, mate and xfce4). It is based on Alpine Linux with all of its ARM packages at your disposal.

Though it was very exciting to have a full blown Linux desktop like Xfce on the phone’s screen, the touch controls were something to be desired. A much better experience can be achieved with Librem’s Phosh. This on the other hand has a scaling turned on (lowered DPI), which messes up a lot of applications so that they become unusable. But it is still closest to a usable working environment.

What I appreciated the most was pmbootstrap which is a CLI tool that lets you configure your custom OS image down to what UI and packages you want to include by default. Thanks to this you have a tailored SD Card ready to be used with your PinePhone.

Arch Linux ARM

My favorite Linux distribution is available for PinePhone as well! Although not customized for it, it is possible to use this and customize it on your own. There is a general guide on installing Arch for PINE64 board, which the PinePhone is based on. There is also a customized kernel that you can use over at xnux.eu with a nice tutorial on how to install it.

I’ve just started with this one, so not much to report apart from that it is working. I have a terminal login prompt on the screen and a SSH connection over a USB cable from my PC. Life is good.

Fedora Mobile

You can install all sorts of things on the PinePhone. I’ve tested this set of shell scripts that help you prepare a Fedora Mobile on an SD Card. A system that was not optimized for this device. The result itself was unusable (at least the release that I tested). Nevertheless I enjoyed learning about the process of preparing a bootable SD Card. Even though it is basically the same for every OS, this set of bash scripts was really easy to study and use it as a tutorial.

Ubuntu Touch

Ubuntu Touch somewhat effortlessly worked to the extend you’d expect with a partially supported device. I liked that they provide an SD Card image for the PinePhone, so all you have to do is to flash it (e.g. using dd) and pop it into the phone.

I personally don’t enjoy Ubuntu for some reason so I won’t experiment with it or comment on this much more.


Did I mention you can run OpenTTD on it? Oh yeah…


Hardware Linux

Root Access to TL-WDR3600

I played around with an old router I had lying around. It is a TP-LINK, model TL-WDR3600 (N600 Wireless Dual Band Gigabit Router). After opening the case you can see a 4-pin connection point that is apparently a serial port. The pinout being 3.3V, GND, TX, RX.

After powering it up with a 12V adapter and connecting to the serial port with a USB-to-Serial dongle you can get to a Linux login prompt. After a bit of searching I found out there is a root account with a factory default(!) password ‘sohoadmin’ [Source].

Logging into the TL-WDR3600 as root gives you a BusyBox shell with an ancient 2.6 Linux kernel. The root mount point seems to be a read-only (flash?) storage, so no fun to be had here. The system would probably need to be re-flashed to change any of the contents.