start use iCloud Keychain instead local keychain issue

Question

I've been used keychain. And now, I'm trying to sync it via iCloud keychain.

I got an exception

result = SecItemUpdate((__bridge CFDictionaryRef)updateItem, (__bridge CFDictionaryRef)tempCheck);
NSAssert( result == noErr, @"Couldn't update the Keychain Item." );

after I've added

[genericPasswordQuery setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecAttrSynchronizable];

to my keychainWrapper init method.

Questions:

1. What do I miss?

2. How can I check, if iCloud Keychain is available?

Euphonious