Swizzling navbar hide methods to tackle this bug http://screenr.com/UEc - No luck.

UINavigationController+Swizzle.m

//
//  UINavigationController+Swizzle.m
//
//  Created by Zsombor Szabó on 11/19/10.
//  Copyright 2010 IZE. All rights reserved.
//

#import "UINavigationController+Swizzle.h"

#import <objc/runtime.h> 
#import <objc/message.h>

void SwizzleClassSelectors(Class c, SEL orig, SEL new)
{
    Method origMethod = class_getInstanceMethod(c, orig);
    Method newMethod = class_getInstanceMethod(c, new);
    if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
        class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
    else
		method_exchangeImplementations(origMethod, newMethod);
}

@implementation UINavigationController (Swizzle)

- (void)_doNothingForSetNavigationBarHidden:(BOOL)hidden
{
	NSLog(@"%s", __FUNCTION__);
}

- (void)_doNothingForSetNavigationBarHidden:(BOOL)hidden animated:(BOOL)animated
{
	NSLog(@"%s", __FUNCTION__);
}

+ (void)_setNavbarMethodsEnabled:(BOOL)enabled
{
	static BOOL swizzled = NO;

	if (enabled == NO)
	{
		if (swizzled == NO)
		{
			swizzled = YES;
			
			SwizzleClassSelectors([UINavigationController class], @selector(setNavigationBarHidden:), @selector(_doNothingForSetNavigationBarHidden:));
			SwizzleClassSelectors([UINavigationController class], @selector(setNavigationBarHidden:animated:), @selector(_doNothingForSetNavigationBarHidden:animated:));			
		}		
	}
	
	else
	{
		if (swizzled == YES)
		{
			swizzled = NO;
			
			SwizzleClassSelectors([UINavigationController class], @selector(_doNothingForSetNavigationBarHidden:), @selector(setDrawingEnabled:));
			SwizzleClassSelectors([UINavigationController class], @selector(_doNothingForSetNavigationBarHidden:animated:), @selector(setNavigationBarHidden:animated:));
		}
	}
}