writeCharacteristicWithoutResponse fails on iOS

[FXschwartz]

Describe the bug After pairing to device, and discovering services. When I attempt to send a command to the sensor the writeCharacteristicWithoutResponse fails with the following error:

[VERBOSE-2:dart_vm_initializer.cc(41)] Unhandled Exception: PlatformException(reactive_ble_mobile.Central.(unknown context at $1061bb1a0).Failure:3, The operation couldn’t be completed. (reactive_ble_mobile.Central.(unknown context at $1061bb1a0).Failure error 3.), {}, null)
#0      StandardMethodCodec.decodeEnvelope
package:flutter/…/services/message_codecs.dart:653
#1      MethodChannel._invokeMethod
package:flutter/…/services/platform_channel.dart:296
<asynchronous suspension>
#2      new Stream.fromFuture.<anonymous closure> (dart:async/stream.dart:247:17)
<asynchronous suspension>
flutter: \^[[38;5;196m┌───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────<…>
flutter: \^[[38;5;196m│ \^[[0m\^[[39m\^[[48;5;196mException: GenericFailure<WriteCharacteristicFailure>(code: WriteCharacteristicFailure.unknown, message: "A service 6E400002-B5A3-F393-E0A9-E50E24DCCA9E is not found in the peripheral 490582D6-5B9D-FFD3-CE73-DD653C8249BA (make sure it has been discovered)")<…>

I'm sure this is something I'm doing. With some context I am attempting to migrate our application from using flutter_blue_plus to this library.

I've tried adding a delay before subscribing to the characteristics as well tried writeCharacteristicWithResponse. It all works perfectly fine on Android just not iOS.

Any help would be greatly appreciated!

Smartphone / tablet

• Device: iPhone 14 pro max
• OS: iOS 16
• Package version: v5.0.2

Peripheral device

• Vendor, model: CUSTOM
• Does it run a custom firmware / software: yes

Additional context Add any other context about the problem here.

[FXschwartz]

@remonh87 Hey Remon, I'm sure you are super busy, especially with end-of-the-year deadlines, but when you get a moment, can you take a look at this issue? Currently, it's the only thing keeping one of my client's projects from being migrated to use this package.

[mashedbymachines]

I also have this problem with a product where we want to send a firmware file over BLE. Using "with response" as a workaround at the moment but it severly decreases throughput. Would be grateful if this was looked into

[FXschwartz]

I also have this problem with a product where we want to send a firmware file over BLE. Using "with response" as a workaround at the moment but it severly decreases throughput. Would be grateful if this was looked into

So using the method writeCharacteristicWithResponse works for you? Because neither works for me.

[mashedbymachines]

I also have this problem with a product where we want to send a firmware file over BLE. Using "with response" as a workaround at the moment but it severly decreases throughput. Would be grateful if this was looked into

So using the method writeCharacteristicWithResponse works for you? Because neither works for me.

Yes on iOS the writeCharacteristicWithResponse method works bit not the one without response. On Android both methods work fine.

However I now see that our error message is different, it is just giving a write permission error when writing without response for us.

I have this problem: https://github.com/PhilipsHue/flutter_reactive_ble/issues/360

[ILittleNiZi]

have you solve this problem? i also have this problem

[FXschwartz]

have you solve this problem? i also have this problem

No, I am still blocked from migrating to this package because of this issue.

[aabdulat1998]

I know this isnt what youre asking but maybe try the following. I set up a subscription stream to the tx characteristic first and then I writeCharacteristicWithoutResponse to the rx characteristic.

[nikolayDemirev]

Declaring the characteristic on the BLE server with a write-without-response flag resolved the issue for me.