Open Radar

 
BLE characteristic writes no longer seem to work under Mavericks 10.9.0.  You can connect, discover, subscribe and read just fine, but every write fails with "Error Domain=CBATTErrorDomain Code=8 "Writing is not permitted." UserInfo=0x1006020d0 {NSLocalizedDescription=Writing is not permitted.}"

This seems to be true whether connecting to virtual hardware (CBPeripheralManager-created peripherals) or real hardware.  I've tested on five machines (two Mountain Lion, three Mavericks), with three devices (one iPhone CBPeripheral, two real BLE devices with write-no-reply characteristics).

It *is* worth noting that all of these machines were upgraded from Mountain Lion to Mavericks, not wiped clean and reinstalled.  However, this is a fairly common situation.

Steps to Reproduce:
1. Use anything that allows you to perform a BLE write.  I'm using my own command-line tool, but I can reproduce this issue with LightBlue from the AppStore as well.

2. Connect to a device that has a writeable BLE characteristic.

3. Attempt to write to the characteristic.

Expected Results:
The value given is written to the characteristic, and the expected result happens.  (Turn on an LED with some Arduino device, receive back a reply from a BLE-based GPS device, you see the value show up in the debugger on an iOS software BLE CBPeripheral, etc.)  On Mountain Lion, this is what happens.

Actual Results:
On Mavericks, the write will fail.  For some programs (LightBlue) this will fail silently, in other cases (my command line tool, etc.) it will show the NSError I described above (CBATTErrorDomain 8, "Writing is not permitted.")  In no case does the device show any sign of receiving the value.

I thought this must be something about my own machine at first, but I have now reproduced this on several machines beyond my own, and in situations both saturated with BLE traffic *and* in an environment with only one or two BLE devices.  I'm thus concerned that this is endemic to Mavericks.

Version:
10.9.0 (13A603)