RE: Android 14 connection issues - repeated GATT 133 errors

Rory Morrison — Fri, 24 May 2024 13:00:00 GMT

Yes, it's very hard to debug because it's so vague as to what the problem is.

We most often get them when trying to re-establish a connection with a device that has gone out of range. In that case of course they are expected as the remote device is "not there" to connect to.

We used to very occasionally get tablets in a similar state where nothing would connect until we turned the tablet off and on, or cleared the Bluetooth cache. This seems to have returned with Android 14, and is happening more often. This is with Samsung Tab A9s, so not particularly low-end.

This discussion here https://github.com/dariuszseweryn/RxAndroidBle/issues/688 seems to be describing a similar issue - it's possible after a certain number of connections the bluetooth stack locks up or runs out of cache memory or something.

Anyway, as I say, it looks like an Android problem, I'm just asking in case someone at Nordic has seen something similar on recent Android versions

RE: Android 14 connection issues - repeated GATT 133 errors

Sigurd — Fri, 24 May 2024 12:13:00 GMT

Hi,

Error 133 - Gatt error is just a generic error. It happens in different occasions. We have observed it on

1) packet collision
2) CONNECT_REQ missed by the target
3) timeout (30 or 20 seconds after connection was initiated)
4) in general, an expected packet wasn't received or an unexpected was.

It used to be much more common in old days, now we see it less and less with new phones/tablets, but the low-end devices could still have problems with this kind of error.