The file was 847 MB. As it downloaded, a chat box opened on the forum.
HVAC_Ghost: Because Carel knows. They have telemetry in the newer controllers. If they see a pirated 1Tool signing in, they can send a kill command. It's not a tool. It's a key. And they can change the locks. carel 1tool software free download
He did not use the work PC. He found an old Dell laptop in a storage closet, one that controlled nothing. He disconnected it from the main network, plugged in a USB-to-RS485 adapter, and clicked download. The file was 847 MB
He called the local Carel distributor.
AsterArjun: Yes. Does it work?
HVAC_Ghost: Mostly. Just don't update the firmware. The handshake patch is fragile. Use it to read, not to write. And delete it after. They have telemetry in the newer controllers