beginBackgroundTaskWithExpirationHandler never gets called

You are actually misunderstanding the function -(UIBackgroundTaskIdentifier)beginBackgroundTaskWithExpirationHandler:(void (^)(void))handler

The block argument called "handler" is what will happen when the background task expire (10min).

To get your code running you need to put your code out of the expiration handler:

UIApplication *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    bgTask = UIBackgroundTaskInvalid;
};

[self ffwButtonPressed:ffwButton];
NSLog(@"beginBG called");
[app endBackgroundTask:bgTask];

Here is a link to the documentation

I ended up not needing beginBackgroundTaskWithExpirationHandler at all. This line solved my problem...

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];