Hi!
I recently lost any functionality of my Dongle after upgrading home assistant from 2024.12 to 2025.4.
I am running Home Assistant OS on a Raspberry Pi 3b+ and it was running fine for about a year until suddenly the dongle could no longer be initiated.
Looking at the error logs, I could see that the devices appeared as locked or busy.
I got some BlockingIOError: [Errno 11] Resource temporarily unavailable
or The serial port is locked by another application
Now I tried removing the device altogether, I downgraded Home Assistant to 2024.12 and finally completely wiped my installation and started a fresh Home Assistant OS. The issue persisted.
Now I found a solution at last!
I used this firmware upgrade tool from Sonoff (pluggin the dongle into my Mac directly). SONOFF Dongle Quick Flasher: Effortless Firmware Updates in 1 Minute - SONOFF Official
And suddenly the dongle was recognized again by Home Assistant.
Iām just here to share this solution because this really had me struggling.