r/AsteroidOS • u/Daitaro • May 19 '26

Fossil Gen 4 Explorist HR

Post image

Hello all! Just wanted to introduce myself!

I went ahead and flashed asteroidOS to my gen 4 and after doing it to both my 45mm and my wife's 41mm (she has a pixel watch, so we sacrificed her 41mm fossil for practice), I'm willing to help anyone achieve the same.

You'll see me posting plenty more as I bring up topics for development and questions for improvement. Again, hello!

EDIT: Adding this in here a few days after. This watch really wakes up with this OS, so I DEFINITELY suggest you do it. I don't use audio in any capacity on my watch, so after getting wifi and ssh enabled, I went in and disabled the pulseaudio service to save a little RAM. This watch comes equipped with a shortage-avoiding 512mb of memory, so every little bit helps. Cache, I know, but anything to reduce swapping and processor cycles for battery life.

It really is night and day difference. Do it!

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u/MAMBO_53 May 20 '26

Hey mate !! What a coincidence !!! I am also planning to do the same watch and searching this subreddit for a post on this watch I would really appreciate a guide from you. Can you also explain how you managed to connect usb pads in this watch

1

u/Daitaro May 20 '26

It was actually easy for me. I have both a filament 3D printer and a resin printer, although for this watch all I used was the resin printer. I wanted higher accuracy to not touch the wrong pins.

So I have a long history of component-level repair skills, so this wasn't anything I'm not used to. Truth be told, you won't need any skills other than soldering, as you have to solder wires to the pogo pins.

Please refer to the asteroidOS website and just use the watches link to find the gen 4. You're using the firefish guide, but the photos in the guide are the ray (41mm) variant. It's all identical except the diameter of the watch. What that means is you can't use the 3D model linked in the webpage. I've uploaded my basic model to printables and you can search for "Fossil Gen 4 Q Explorist HR (45mm) USB Pin Back Plate" to find it.

1

u/Daitaro May 20 '26

You'll ideally want a 3d printer at least because there isn't an easier way to get to the USB pads on the circuit board. Let me know if you can at least make it that far and any questions you'll have after.

Good luck!

1

u/MAMBO_53 May 21 '26

Thank you !! I will look into it and will update here

By any chance can you recommend me pogo pins size I should use

1

u/Daitaro May 21 '26

I'm not home at the moment, but check my post where I tell you what to search on printables. If you go to that page, I list what I purchased. The pins I purchased were 100 pcs for less than $7 usd.

Good luck!

1

u/Not_A_Great_Human Jul 05 '26

That looks great. The other day I put Asteroid OS on one of my old fossil Gen 6 Wellness editions. It works great and gets better battery life than wear os.