I am running SUP 2.1.2 and have an object API program for an
MBP with a 'BIGBINARY' attribute. The MobileSDK generated
code that defines the type as SUPBigBinary in the
GeneratedCode files. Object API documents for 2.1.2 provide
pretty clear examples of the use of SUPBigBinary but I have
found that in practice the class does not work. The docs
provide an example of use:

SUPBigBinary *image = book.cover;
NSData *data;
[image openForWrite:[data length]];
[image write:data];
[image close];

Calling openForWrite: results in an 'unrecognized selector
send to instance...' type of message. It almost feels like
this is a pure abstract class, but I am perplexed that the
generated code for the MBO would contain an abstract type?
I would fall back to a sized binary type, but in practice we
have found the reliability of the MobileSDK to be terrible
when making changes to data structures / types.

Ideas and corrections welcome.