Notes on Apple Core Bluetooth Peripheral ID

  • The only peripheral ID that Core Bluetooth API offers after discovery is CBPeripheral.identifier.
  • Not MAC address.
    You can’t get MAC address via Core Bluetooth. There is no public API for this. If this is an internal or jailbreak application you can get the value of the kLockdownBluetoothAddressKey key via liblockdown.dylib.
  • It’s obtained via callback function didDiscoverPeripheral. (iPhone acts as central device)
  • Type is NSUUID, not CBUUID. UUID is deprecated as of iOS 7.0.
  • identifier has been moved to CBPeer class, which is base class of CBPeripheral. So net effect is the same.
  • A different central will return a different id for the same peripheral.
  • A central will return the same id for a peripheral. Thus, it can be stored and used later per Apple doc.
    However, I don’t know how long it will return the same id.
    Important: assuming the peripheral doesn’t use Bluetooth 4.0 Privacy feature, which changes its ID periodically.
  • Peripheral MAC & central id (& possible time) is used (by Core Bluetooth) in generating this CBPeripheral.identifier.
Notes on Apple Core Bluetooth Peripheral ID

Xcode Error – Could not launch app – No such file or directory

I got this annoying error with Xcode 4.6.1: Could not launch app – No such file or directory Error.

Xcode was working for me for awhile without problem with my iPhone. A friend wanted me to install an app on his phone. And I got this error.

It turns out that the “Deployment Target” (=IOS 6.0) is higher than that on the phone IOS 5.1.1.

I hope it helps,

Xcode Error – Could not launch app – No such file or directory

iOS console log using ASL

If you want to get iOS console log, you can use below code:

NSMutableArray* mainList = [NSMutableArray array];
aslmsg q, m;
int i;
const char *key, *val;
q = asl_new(ASL_TYPE_QUERY);
aslresponse r = asl_search(NULL, q);
while (NULL != (m = aslresponse_next(r)))
    NSMutableDictionary *tmpDict = [NSMutableDictionary dictionary];
    for (i = 0; (NULL != (key = asl_key(m, i))); i++)
        NSString *keyString = [NSString stringWithUTF8String:(char *)key];
        val = asl_get(m, key);
        NSString *string = [NSString stringWithUTF8String:val];
        [tmpDict setObject:string forKey:keyString];
    [mainList addObject:tmpDict];
iOS console log using ASL

iOS accessory bug:

After extensive testing, I found a big IOS external accessory bug in iOS 5.x.x – 6.1.2 detailed below.
I submitted the bug to Apple and got confirmation that they are aware of it but they can’t share anymore detail. A fix may be in next version! Standard Apple secret procedure.

EAAccessory object returns no protocol string (even with accessory attached) after iPhone wakes
up from deep sleep
Steps to Reproduce:
– Put iPhone with app into sleep for 3 hours (or overnight) by pressing power button.
– Wake up iPhone using home/power button.
– Print out the protocol string as below:
NSArray *accessories = [[EAAccessoryManager sharedAccessoryManager] connectedAccessories];
for (EAAccessory *eaa in accessories) {
NSLog(@”protocol %@”, eaa.protocolStrings);
– We tried to put in 6s retry timer but it doesn’t help.

iOS accessory bug:

iphone 3.0 dev: Hello World!

I’m late in the iPhone gold rush. Nevertheless, it’s hottest thing right now. So I need to learn it. Here is my journey:

  1. Buy a Macbook Pro with Snow Leopard CD.
  2. Install Snow Leopard.
  3. One nice thing about Snow Leopard CD is that it includes latest Xcode 3.2 in “Optional Installation” directory.
    Install Xcode 3.2.
  4. Download iphone 3.0 SDK for Snow Leopard from
    Install iphone 3.0 SDK.
  5. Download Hello World example from
  6. Run Xcode and open Hello World example project.
iphone 3.0 dev: Hello World!