Van Rysel D100 drops Bluetooth after ~2 minutes – every app, every device

Hi everyone,

I'm stuck with my Van Rysel D100 and hoping someone here has seen this before.

The problem:

I can connect to the trainer normally and power shows up fine. But after almost exactly 2 minutes the connection drops, every single time. After that the trainer hangs: the LEDs still show "connected" (solid blue), it doesn't show up in any scan anymore, and I can only reconnect after unplugging the power. Then it drops again after 2 minutes.

If I don't connect at all, the LEDs blink blue for about 2 minutes and then turn off completely. In that state my phone can't find the trainer anymore, but my laptop (Chrome) still lists it as "Paired". Connecting doesn't work though. Once, both LEDs even stayed solid red.

What I've already ruled out:

\- Apps: Pushing Limits, OnelapFit, Zwift and the diagnostic app nRF Connect. All drop after \~2 minutes.

\- Devices: iPhone, iPad and laptop all behave the same.

\- Signal: -49 dBm in nRF Connect, phone right next to the trainer.

\- Interference: all other Bluetooth devices and Wi-Fi smart plugs switched off.

\- Pedaling: it drops even when I'm not pedaling at all.

\- Firmware: latest via OnelapFit (version \[enter here\]).

\- Power: wall socket, no power strip, power adapter LED is solid green.

The strangest part: I borrowed an identical D100 from a colleague, and at my place it shows exactly the same fault.

My questions:

\- Has anyone seen this 2-minute disconnect on the D100 (or the identical Magene T110)?

\- Is there a way to factory reset the trainer or reflash the firmware?

\- Any idea what at my place could be causing this, given that two trainers show the same fault?

Thanks for any ideas!