COROS Replaces Watches Bricked by Firmware Update
You update the firmware on your watch and think nothing more of it. A few days later, the device will not turn on. For some COROS owners, the last few weeks have gone exactly that way. The manufacturer has acknowledged the problem and is replacing the affected watches.
What actually went wrong
The story was first reported by DC Rainmaker, one of the most trusted reviewers in endurance sports tech. According to his reporting, reports have clearly risen of COROS watches that stop working after the firmware update from mid-May 2026.
The most deceptive part is that the failure usually does not happen right away. The watch keeps working normally, then stops turning on days or weeks later. Warning signs sometimes appear first: odd behaviour, a sharp drop in battery life, and in some cases a sticking rotating crown. Because of that delay, it is hard to connect the failure to the update.
In practice, this is bricking. The device stops responding to charging or to restart attempts. Once a watch fails this way, there is no rolling back to a previous firmware version and no reviving it on your own. For a triathlete mid-season, building training around heart rate and power data, that is losing your data rhythm at the worst possible time.
COROS acknowledges the problem and replaces the hardware
This is where it gets better, because COROS has not swept the issue under the rug. The company is replacing the affected devices. Darian Allberry, Head of Product Marketing and Support, confirmed it on 17 June 2026:
For anyone who reaches out to us and whose device has failed following the recent firmware update, we are replacing those units.
Darian Allberry, COROS, quoted by DC Rainmaker
That is a translation of the original statement, but the meaning is clear. If your COROS failed after the May update, you are entitled to a replacement. You do not need to prove you did anything wrong. The manufacturer shipped a faulty update. The scale is clear from a figure the company itself provided: within a 72 hour window, over 100 reports came in about watches that had stopped working.
Which models are affected
To be straight about it, COROS has not published a closed list of models. What the company has said points to one thing: the problem is hitting watches that are two to four years old the hardest. The most frequently reported model is the COROS PACE 3. The company notes that this is partly a statistical effect. The PACE 3 is its best seller, so it naturally generates more reports. Treat that as a pointer to where the risk is highest, not as a list of condemned models.
What to do right now
- If your watch failed after the May update: contact COROS support. Mention the firmware-update failure, since the company’s own statement means a replacement is owed to you.
- If your watch still works and you updated it in May: do not force anything. Resetting it or reflashing firmware blind makes no sense while the device is working.
- Regardless of the above: sync your data to the app regularly, so a failure does not cost you your training history.
The whole episode is a reminder of an old truth: a firmware update is not always a clean win. Sometimes it pays to wait a few days after release and see whether other users are reporting problems.