Please make sure to test all hardware functions of your watch in your current operating system to rule out hardware defects before installing AsteroidOS. You can report any hardware support issue here. Use the label ray/firefish for issues specific to your watch.
The following list shows the state of the features of the firefish version of this watch.
goodDisplay
goodTouch
goodBluetooth
goodHaptics
goodTilt-to-Wake
goodLight Sensor
goodAlways-on-Display
badMicrophone
goodHeart Rate
goodUSB
goodWLAN
badGPS
badNFC
goodCrown
The following list shows the state of the features of the ray version of this watch.
goodDisplay
goodTouch
goodBluetooth
goodHaptics
goodTilt-to-Wake
goodLight Sensor
goodAlways-on-Display
badMicrophone
goodHeart Rate
goodUSB
goodWLAN
badGPS
badNFC
goodCrown
Model Number
Model Name
Codename
DW6A1
Armani Exchange Connected Drexler
firefish
DW6B1
Misfit Vapor 2 (46mm)
firefish
DW6F1
Fossil Q Explorist HR Gen4
firefish
DW6D1
Diesel On Full Guard 2.5
firefish
DW7B1
Misfit Vapor 2 (41mm)
ray
DW7E1
Emporio Armani Connected Matteo
ray
DW7E2
Emporio Armani Connected Alberto 2018
ray
DW7F1
Fossil Q Venture HR Gen4
ray
DW7F2
Fossil Q Sloan HR Gen 4
ray
DW7K1
Kate Spade Scallop Smartwatch 2
ray
DW7M1
Michael Kors Access Runway
ray
DW7M2
Michael Kors Access Sofie HR
ray
DW7S1
Skagen Falster 2
ray
DW7T1
Tory Burch ToryTrack Gigi
ray
DW7T2
Tory Burch ToryTrack Tory
ray
Model number and variants
The Fossil Gen 4 is marketed as different versions from different manufacturers.
This means that there are two known versions that are compatible with a range of Fossil Gen 4 watches.
These two versions are referred to as firefish and ray. One difference between the two is that firefish has a larger display than ray.
Generally, models that start with DW6 are compatible with firefish. Models that start with DW7 are compatible with ray.
USB connection
The Fossil Gen 4 doesn't expose a USB connection. It is however possible to connect to the watch using an adapter cable.
You will need access to the USB pads on the watch, this can be achieved by removing the plastic back cover. Using heat and a prying tool, it is fairly straightforward to remove. Pay attention to the flex cable that connects the back cover to the topside of the PCB. It is recommended to start prying on the side opposite of the buttons.
You should make a custom dock to connect a USB cable to the watch. Soldering directly to the watch USB pads is a bad idea since those are very thin and break easily. The image below indicates the function of each pad.
A 3D printable dock that can be used to interface with the watch, but requires pogo pins, is available to download here: https://www.printables.com/model/264488-skagen-falster-2-usb-dock. This is only tested with the Skagen Falster 2, other variants have different dimensions and might be incompatible.
Extract the content to a folder of your liking.
Navigate to that folder using the Windows commandline (cmd.exe).
Instructions
1. Unlock your bootloader
Note
Unlocking the bootloader may void your warranty.
The unlock process will trigger a factory reset of Wear OS. Backup any data you do not want to loose.
Warning
DO NOT relock the bootloader while having AsteroidOS installed. This puts the device into a non-recoverable state.
Installing and booting AsteroidOS requires an unlocked bootloader.
Accessing the fastboot bootloader menu on your watch can be achieved either by using ADB in Wear OS or by manually stopping the boot process at the fastboot screen.
If you are familiar with the manual method to access the bootloader menu on your watch, you can skip to step 1.3. Those methods are explained on the useful commands page.
To boot into fastboot menu from ADB within WearOS, follow steps 1.1 to 1.2.
1.1 Enable ADB on your watch
1. Open the settings app
2. Open the System page
3. Open the About page
4. Tap the Build number 7 times to reveal Developer options
5. Open the Settings app again
6. Open the Developer options page
7. Enable ADB debugging
1.2 Reboot to fastboot bootloader mode
Enter the following ADB command in a terminal with your watch connected to USB.
adb reboot bootloader
1.3 Use fastboot to unlock the bootloader
With your watch now in fastboot mode, enter this command in a terminal to start the unlock procedure.
fastboot oem unlock
1.4 Follow the instructions on your watch's screen
Please note again, this may void your warranty and will wipe your userdata.
1. Reboot into fastboot bootloader menu
If your watch can be booted into AsteroidOS, all of the below described methods work to access the fastboot menu on your watch.
In case AsteroidOS can not be booted successfully, use the manual method.
1.a Manual method
Long press the power button for up to 10 seconds until the watch reboots. Then quickly perform a key combination or sequence right when the watch powers on again, to stop the boot process at the fastboot screen. The specific key combination for your watch is explained on the useful commands page.
1.b Using ADB
Set ADB Mode in the USB page of the AsteroidOS Settings app.
Enter the following ADB command in a terminal with your watch connected to USB.
adb reboot bootloader
1.c Using SSH
Set SSH Mode in the USB page of the AsteroidOS Settings app.
Enter the following SSH command in a terminal with your watch connected to USB.
ssh ceres@192.168.2.15 "reboot bootloader"
2. Install and boot AsteroidOS
2.1 Choose your installation type
Try AsteroidOS as a dual-boot by sideloading the AsteroidOS system image and boot it only temporarily.
This a good way to try if AsteroidOS meets your requirements. Or in case you don't plan to use AsteroidOS daily and intend to not permanently replace your previous OS.
The only differences compared to a real installation are very limited disk space and the necessity to manually boot AsteroidOS on every restart.
Replace WearOS definitively by flashing the system and boot image.
The real installation provides the best experience, but it is advised to make a backup of your previous OS first.
We highly recommend to first test if AsteroidOS meets the requirements of your usecase by performing the non invasive temporary installation before permanently replacing your previous OS.
Note that in the instructions below, firefish is used as part of several file names. For ray, simply substitute that name in each file name.
2.2 Real installation using Linux
While your watch is in fastboot bootloader mode, flash the userdata partition:
Reboot to Wear OS, re-enable Developer options and ADB debugging like shown in steps 1.1.1 - 1.1.7.
Note, you can access the Wear OS settings app via long press of the power button already while the initial pairing screen is shown.
Reboot to Wear OS, re-enable Developer options and ADB debugging like shown in steps 1.1.1 - 1.1.7.
Note, you can access the Wear OS settings app via long press of the power button already while the initial pairing screen is shown.
See the wiki for synchronization clients, SSH access, watchface and package installation, backup guide and much more!
Installation Troubleshooting
Boot problems
Bootloop of any kind or stuck boot process
Don't panic. None of the commands we advised you to use can damage or brick your watch permanently.
You can always go back to the fastboot bootloader menu, by using the manual finger combos for your watch.
Verify that you used the correct image files
Some devices like the Asus Zenwatch 2, the Fossil Gen4 models and the MTK6580 watches have more than one system image supplied, for different variants with slightly different hardware. Most watches have a graphical fastboot menu that shows the correct codename for the watch. Others need to be identified using the hardware differences noted above in the install section.
Clean your watch and charger contacts
Even in case the fastboot flash process succeeds with no errors, it can still silently fail due to connection problems caused by dirty contacts. Clean the pins and pads with isopropyl alcohol. Ideally using that old toothbrush you keep around for electronics cleaning or a microfiber cloth. Carefully sanding the contacts (e.g. with a nailfile) can help in case of obvious corrosion.
Ensure a stable USB connection
Put the watch and your computer on the same flat surface. Try to not move the cable connecting your computer and the watch during the whole flashing process. In case of worn or corroded contacts and pogo-pins that lost their springiness, it might be useful to attach the watch to its cradle or charging cable using duct tape or rubber bands.
Repeat the flash process
Some users have reported needing up to five flashing attempts for a successful result. There is a small chance that the image files were corrupted during download. To guard against this, it's recommended to verify the checksums. Download the SHA512SUMS file (
firefishray
) and verify the checksums with sha512sum --check SHA512SUMS. The checksums for both files will be checked.
Boot gets stuck even after repeated reflash
Congratulations, you might have found a new issue for us to solve. While this should not happen with stable builds, the nightlies are advancing quickly, and are not tested on all watches. You are likely using a nightly build, as the installation pages currently link to those. You can try again and install a stable build when available. To help us solve the problem, you could try to collect logs. It is possible that the watch does not show a UI but is already accessible using ssh ceres@192.168.2.15 or adb shell in the state the boot process stops. In case SSH connection works, try the following commands to write logs to local .txt files.
or, if your watch presents an ADB interface, use the following commands:
adb shell journalctl > journal-watch.txt
adb shell "/system/bin/logcat" > logcat-watch.txt
In case no connection is available, it is still interesting to see if the watch leaves any traces in your local dmesg. Try to spot USB related messages in sudo dmesg -w while the watch is connected and booting. Record the log using the sudo dmesg > dmesg-local.txt command.
You can share those logs in a new Github issue tagged with the watch codename. For support chat, you are invited to join our Matrix channel.
Watch only boots when powered via USB, but shuts off when booted while worn
This is a clear sign of a worn battery that will soon fail. Maybe you should replace it. The boot process of AsteroidOS uses all cores of a watch to ensure a fast startup. This leads to power spikes during the boot process, which can completely shut down watches with worn out batteries. It has been observed that WearOS can still boot on watches with worn out batteries, but AsteroidOS cannot, depending on the progress of battery wear. However, AsteroidOS can usually still provide a useful 10-20 hours of uptime when the watch is worn once booted while powered up. Batteries are relatively easy to replace on watches with screwed down backs. Glued back plates usually require creative solutions involving hair driers.
Watch successfully boots into the AsteroidOS user interface, but immediately reboots
This is a known behavior when the battery charge is very low. The watch usually recovers from this condition by simply boot cycling for some time. All watches also charge in fastboot or recovery mode. Letting the watch dwell on the fastboot or recovery menu screen for some time should fix the problem even faster.
Flashing problems
Watch is not detected and all fastboot commands fail
When using Linux,
try prepending sudo to the commands to execute them with root privileges. If that works, you are missing UDEV rules for Android devices that would allow your user to execute the commands. Many package managers provide the android-udev-rules, which avoids the need to manually set up these UDEV rules. If the package is not available on your system, you can follow the instructions at the official android-udev-rules repository.
On Windows systems,
this usually happens due to driver issues. If you have installed an Android USB driver other than the official Google USB driver that we link to in the installation fields above, please remove it. Then reinstall the Google USB driver or update it by installing a possibly newer version. We find that the Linux fastboot drivers are more reliable. It is very easy to create a bootable live Linux USB stick, for example, following these instructions at askubuntu.com, and then follow the above Linux installation commands after booting the live Linux USB stick.
USB 3.0 ports
have caused all kinds of random and hard to track problems for many projects using ADB and fastboot. If your ADB and fastboot still can't connect after following the steps above, it might be worth switching to a USB 2.0 port. If your shiny new computer no longer has such a port, a cheap USB 2.0 HUB may help.
ADB connection works, but fastboot does not?
The fastboot oem unlock command not working even though the watch could be booted into fastboot mode using adb reboot bootloader is a known issue on windows systems. It is caused by using a watch manufacturer USB driver with missing fastboot support. Try removing that one and install the offical Google USB driver we linked above in the install section.
Fastboot command crashes or hangs at "invalid sparse file format at header magi" (explicitly missing the "c" in magic)
This error occurs when using deprecated fastboot and ADB versions on Windows systems. If you already had adb.exe and fastboot.exe installed and skipped downloading our supplied ZIP file, please install and try those commands instead. Another reliable source for updated windows ADB and fastboot versions is the official Google platform tools ZIP file.
Fastboot command stops with error during the ~5 minute flashing process
Smartwatches are prone to lose a proper connection to their cradle over time due to sweat corroding the watch pins. Clean the pins and pads with isopropyl alcohol and repeat the flashing process. Try to ensure a stable USB connection by putting the watch and your computer on the same flat surface. Try to not move the cable connecting your computer and the watch during the whole flashing process. In case of worn or corroded contacts and pogo-pins that lost their springiness, it might be useful to attach the watch to its cradle or charging cable using duct tape or rubber bands.
Fastboot command displays "invalid sparse file format at header magic" when starting to flash the device
This is not a fatal error and can safely be ignored. Fastboot expects images to be in sparse format. When a raw image is supplied like in case of most of the AsteroidOS watches, fastboot converts it to sparse and shows above message.
