Onvis HS2 button, timing out when attempting to add via bluetooth proxy

Configuration
1

Hi there,
I am attempting to add an Onvis HS2 smart button to Home Assistant via bluetooth proxy but am unable to do so. HA sees it immediately when the device is reset and it pops-up on the Integrations page as a discovered Homekit device. However after I click configure, I am prompted to enter the set-up code, which I do but then after about 30 seconds I receive this error message and am unable to add it:

“An unhandled error occurred while attempting to pair with this device. This may be a temporary failure or your device may not be supported currently: Timeout waiting for BluetoothGATTReadResponse, BluetoothGATTErrorResponse, BluetoothDeviceConnectionResponse after 30.0s”

I am absolutely certain I am entering the correct set-up code listed on the device and I have tried 2 different ESP32 proxys. The device is brand new and has never been added to any Homekit/Apple network (infact I own no Apple devices). I have read some similar posts on the Onvis HS2, but have not gained any insights to what may be the issue. Any ideas would be appreciated.

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I can confirm this method worked last time I tried it (Feb 2026 maybe?).

Those buttons are super cool devices but HA effs up their configuration/integration every other release. The 2026.6 borked them again for me, and the method of removing them and re-adding them, that worked for the past year, lead me to your post.

IDK exactly why, if it's just my setup, but here I am again back to controlling my lights with a smartphone.

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I'm having the same problem... Did you ever find a solution?

I've tried the ESP32 bluetooth proxy as well as pairing it via Apple Home on iPad. (I don't have an Apple home hub or anything like that, so I don't know if that would even work)

By doing it with the ESP32 proxy, it shows up as a Homekit device in HA Devices page, but when I try to add it by entering the pairing code, I get the same timeout error.

I saw somewhere that you might have to create a temporary pairing code via the Apple Home app but I don't see the "Turn on Pairing Mode" option that was mentioned on some other posts.

Is Homekit-over-Thread a normal thing? I thought people would mostly use Matter-over-Thread so this caught me off guard.

Thanks!!

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Replying to myself here- My issue ended up being a bug in the espressif BLE stack: Bluedroid HCI: ACL fragment reassembly failure during rapid BLE indication bursts (IDFGH-17460) · Issue #18414 · espressif/esp-idf · GitHub
It hasn't been released yet but I patched it locally with the same fix and was able to add the HS2 to HA and move it over to the Thread network (Sonoff Dongle Plus MG24 running openthread firmware)