Furilabs FLX1s

• Performance: 4/5
• Affordability: Great price for the hardware and support provided
• Compatibility: 3/5
• Battery Life: 5/5

Setup information

• OS: FuriOS 14.0.2
• Kernel: 4.19.325
• DE: Phosh

Introduction

The furilabs FLX1s is the sibling device of the FLX1. After the launch of the FLX1 devices they ran into issues trying to source more batches from their Original Design Manufactuer (ODM). They decided to continue moving forward and work with a new factory to design a new device from the ground up with the same SoC as the base. With the SoC being the same devices this allows them to continue development that benefits both the FLX1s and FLX1 devices with minimal changes thus providing a major benefit to existing FLX1 users.

The FLX1s dubbed the slim, is a more compact and easy to carry phone. The furilabs team were more involved with the design of this phone compared to the FLX1 so they targeted features that would have the most impact on the user experience and left out some feature that were less critical especially in the linux environment. Some of the differences are great for some users but could also be a potential deal breaker for others as such the differences are listed below as a table, if you want the full specs you can check out the official website.

The hardware switches are a nice addition to the phone and use a similar design to the librem 5 where they are positioned on the side and easy to use unlike the dip switches on the back of the pinephone that requires removal of the back panel. The lack of the removable battery and waterproofing is a bummer but I know the waterproofing itself causes issues due to the testing and certification process whenever changes need to be made. The reduction in screen resolution isn't to big of a deal to me and can actually bring with it better gpu performance in some cases like games and 90hz is still a big improvement over the 60hz that other linux phones have. The modems themselves also seem to support different bands due to firmware differences between the two ODMs with the FLX1s having more bands supported, hopefully this will make its way back to the FLX1 in the future. The shell quality is also a downgrade over the original FLX1 with it being a more brittle and plasticy feeling material though this can be remedied by utilizing a phone case.

Hardware Supported

Hardware	Supported
GPS ²
aGPS ¹
Cameras
Microphone
Bluetooth
Modem
Accel/Tilt/Step/Wake
Orientation/Gyroscope
Light/Pressure
Proximity
NPU

¹ Not hardware but important usability feature and is optional ² GPS seems to struggle finding a fix indoors

Some hardware is a grouping as those are all functions handled by a single sensor on the device and exposed as different metrics.

Cell Service

Cell service was tested in the US utilizing US Mobile MVNO, referral link, as it allows for easy testing of the 3 major US network providers. The only downside is the TMobile service has deprioritized download speeds so your speeds can be on the slower side like mine based on location and network traffic. Download/Upload speed tests were done using ookla speedtest.net and netflix fast.com with the data waster option enabled. As service seems to vary from moment to moment, I ran multiple tests and grabbed the best results for each section.

Light Speed (Tmobile) seems to work great without any issues. While the FLX1s does support the bands for 5g, the 5g connection in the US seems to be unstable and causes issues as a result I have disabled the 5g bands. I have seen reports that lots of people outside the US use 5g without any issues. Dark Star (AT&T) along with Warp (Verizon) do not work as the upstream carrier have blocks in place for phones that have not gone through their certification process, which furilabs as a small company has not had the resources to go through.

I use my JMP.Chat eSIM adapter and it works perfectly and even has a built in way to change profiles and add new profiles, it is clunky but it is enough to get the job done. It does not work with eSIM Manager, hopefully it will in the future or the built in app is improved as adding new profiles is a bit of a hassle.

US Mobile Light Speed (Tmobile)

Phone	Tech	Speedtest down	Fast down	Fast up	VoLTE / VoNR
FLX1s	4G
Pixel 6	5G
Pixel 6	4G

Performance

The FLX1s is a fast phone in general. The Mediatek Dimensity 900 is fast especially compared to pinephone/pinephone pro/librem 5 devices. It comes with 8GB of RAM, which is a nice improvement over the FLX1 6GB which is nice when having to rely on andromeda for some of your android apps. Web browsing and media playback are fast and smooth. Android container is fully supported with acceleration working well and the performance is great. There are some acceleration issues with flatpak qt6 based applications due to upstream QT flatpak gles issues. Flatpak qt5/gtk4 and native qt5/qt6/gtk4 are all accelerated and seem to be working without issues.

Compatibility

The FLX1s is a halium based device so it is limiting to what OS/DE you can run on it. Currently you can run both FuriOS and Ubuntu Touch, though FuriOS is the only one officially supported by the FuriLabs team. You wont be able to run any of the other mainline OS though like arch and postmarketos. For desktop environments (DE) you are also limited to Phosh in FuriOS and Lomiri in the Ubuntu Touch port. GTK based applications seem to function the best while some QT based applications have issues such as acceleration and/or failing to launch. The FLX1s also supports multiboot allowing you to install multiple OS side by side. This makes it simple to test new changes without breaking your main image or even testing out separate different OS as they are released. The app they created to manage this is bootman and once an OS is integrated with it then its as simple as telling it to create a new partition of X size and telling it what OS to flash onto the partition. It will then show up as a touch interface when turning the phone on to select what OS/Partition you want to boot into.

Android

Android support is amazing with lots of sensors passed through to the container, listed below. The android system is called Andromeda which forked off Waydroid and has made tons of improvements and updates to the base android system. You should be able to run most android applications without any issues except the usually culprits that have Integrity API (Safetynet replacement) like banking apps. Video playback works and I can confirm Grayjay works perfectly except the volume control guesture control. Android also integrated perfectly with the rest of the host OS with all your android applications showing up in the app drawer.

There is a gnome software plugin so you can search and install android apps from fdroid through the gnome software store as if it was a native application removing the need to manually open fdroid. There's a android section in the gnome settings that exposes a lot of android settings to the user as shown below. Enabling the Shared Folder setting allows you to have full access to files in both directions so you can take pictures within the linux environment and share them within android apps and vice versa, download files from android apps and access them within the host linux environment. On the host the android files are located under ~/Android and within android the host files are located under ~/Linux.

Sensors passed to Android

Tested using Sensors Toolbox app

Sensor	Passed through
GPS
Cameras
Microphone
Bluetooth
Modem
Accelerometer
Geomagnetic
Orientation
Gyroscope
Light
Pressure
Proximity
Gravity
Linear Acceleration
Rotation Vector
Step Counter

Docking

The FLX1s like the FLX1 does not support usb dp-alt mode but they are still able to utilize evdi to get output externally. They have also developed an app that allows for wireless casting of media content directly to an external display via miracast though it seems to not work on every wireless display.

Web Browsing

Web browsing works really well. Firefox runs well and comes with a custom configuration similar to postmarketos mobile-config-firefox for a better experience on mobile screens. Benchmarking results with speedometer 3.1 and webgl aquarium test with scale set to 100% are below. The aquarium test shows every fish count preset to show how the fps scales with the number of fishes.

Based on results I would recommend sticking with firefox. If you do have andromeda running in the background then running firefox in it is also a great option as performance is amazing and it scales perfectly. Epiphany while having a nice mobile design, seems to suffer from some performance issues due to some webkit bugs that the flx1s runs into. Angelfish runs but since it is qt6 it is missing hardware acceleration and also requires disabling the qt webengine sandbox due to chromium complaining about suid on bwrap.

Speedometer 3.1

¹ Fails to launch

WebGL Aquarium

Angelfish isn't hardware accelerated so no fishes for angelfish :'(

¹ Estimated range as the fps seemed to fluctuate a lot while running making it hard to see actual numbers

Media Playback

Below is a table of different video codecs and their playback performance. The hardware has support for decoding h264/h265/vp9 and they are working on adding in the software support necessary. The best results for native seem to come from MPV/Celluloid/firefox so as long as you are using any of those performance should be fine and inline with each other.

Player Information

H.264/AVC

Player	1080p@30	720p@30
MPV
Clapper	¹
Livi
Celluloid
Firefox
Andromeda Firefox

H.265/HEVC

Player	1080p@30	720p@30
MPV
Clapper
Livi	²	²
Celluloid
Firefox
Andromeda Firefox

AV1

Player	1080p@30	720p@30
MPV
Clapper		¹
Livi
Celluloid
Firefox
Andromeda Firefox

VP9

Player	1080p@30	720p@30
MPV
Clapper
Livi	²	²
Celluloid
Firefox
Andromeda Firefox

¹ While plays smoothly it seems to have a stutter like if frames are sometimes played out of order

² No video output at all

Camera

The phone does not support libcamera and megapixels like mainline linux phones. Instead it has it's own camera stack and exposes the cameras out via v4l, gstreamer, qcamera and pipewire. This allows it to be used universally by other applications. For example for video chatting through firefox. The camera application opens up quickly. It can also capture video with audio correctly in sync. The phone has 3 camera sensors and all them are supported and exposed individually. There is no advance mode to manually control WB, ISO, codec, etc but it does have tap to auto adjust the focus/wb/iso and it works really well.

Library	Supported
Libcamera
Droidmedia
CameraProvider

Abstraction Layer	Supported
LibMegapixels
v4l2
Gstreamer
Qcamera
Pipewire

Example

Flashlights were pointed at the ceiling and everything left on auto, Pixel 9 and Iphone 12 both have a night mode where it took 3s for the low light photos

Normal Temp Medium Light

FLX1s	Pixel 9	iPhone 12

Normal Temp Low Light

FLX1s	Pixel 9	iPhone 12

Low Temp Medium Light

FLX1s	Pixel 9	iPhone 12

Low Temp Low Light

FLX1s	Pixel 9	iPhone 12

Battery Life

The phone has amazing battery life with the screen on and on standby. Standby is also different from the mainline devices as it does not use deep sleep. Instead it uses a low power mode, this allows it to continue running applications and keep network alive. This has the major benefit of allowing you to ssh in at anytime and continue to receive notifications from all apps including web based apps. Charging speed is also great supporting Power Delivery at 10v 3a allowing you to get multiple hours of battery life with just a handful of minutes on the charger.

Testing was done using the following settings:

• Screen brightness set to 50%
• Screen timeout disabled
• Measured from 100% battery to device shutdown
• Without android unless specified
• With sim unless specified
• With Wifi enabled
• Video playback is 720p 30 fps no audio
• Charge time tested on pinepower v1 desktop
• Prometheus polling
  • Standard: every 15 seconds
  • Standby: every 30 minutes
  • Charging: every 5 seconds

Screen Time

Video Playback

Standby

Charging

Charging Curve

• Measured from Sonoff S31 running esphome

Support

Support from FuriLabs has been outstanding. They are all constantly in the telegram group so when issues are discovered by endusers and they mention it in the chat they are able to immediately replicate it on their side so they can troubleshoot and fix it. They also have a great system to allow users to test fixes similar to Ubuntu Touch where there is a new repository for each fix that the user can install and uninstall. While UT requires the user to use the terminal to install said repository the FuriLabs folks have instead decided to create a GUI so even users that are terminal shy can test fixes and provide feedback. Overall getting ahold of them and getting software support from them is amazing but I have yet to interact with them when it comes to hardware defects so I can't comment on their warranty experience.

Conclusion

This is a great device for the price when you consider both performance and support. The phone has just gone through its first set of updates with tons of fixes and improvements compared to out of the box. Since it is still very new there are issues that are appearing that the team is working through fixing. The phone is great to use and the battery life is amazing. The camera is good and better than the primary mainline linux phones I have tested, pp/ppp/l5. The only downside is the lack of software support for other OSes and DEs but that is expected with a halium devices. The docking situation is an envolving situation with promising results coming soon. The quality of the devices coming out of the factory for the initial batch seemed to have some cosmetic issues with some users having some of the screen glue seeping out and others with small cracks in the frame but the team is currently looking into those and will hopefully be able to work with the factory to reduce those problems. The quality of the plastic used for the house also doesn't scream quality but its the kind of thing you would not notice once the phone is in a case, which is a lot easier to do as it is not as thick as the FLX1. Even with those caveats it is still a great device to use and I would 100% recommend it to anyone looking for a linux phone that is usable as of today as long as you are ok with the limitations of a halium device.

My Involvement / Disclosures

I've followed Bardia, the CEO, development over the years across different devices prior to founding FuriLabs, while he was working on Droidian. While he was working on droidian, I financially donated to him in order for him to acquire hardware. I have purchased the FLX1 as soon as it was available for purchase and have daily driven it for the past year.

The FLX1s was sent to me for free for assisting in development and review but this is all my own information and opinions. I do minimally contribute to their development, mostly on the user side of things like their gallery app, bootman and andromeda system. Everything I've contributed on the software side is open in my Github and tagged as such on their official repos. I also currently participate in their software QA testing prior to its public release when I have time. My FLX1s is also available for them to utilize for developing and testing fixes for US specific problems that they are unable to replicate in their country such as the modem 5g issues that exist in the US but work for them in Canada and Spain.