Replace custom back button with default - ios

Question

There is a lot of questions about how to replace the default back button with a custom back button, but none that I know of about how to replace a custom back button with the default.
I have a web view that when [self.webView canGoBack] == YES, a custom back button appears. But after you go back all the way, that custom back button is still there, rather than the default. Is there something I can do to replace my custom back button with the default when [self.webView canGoBack] == NO?
Here is my relevant code:
#interface MerchViewController () <UIWebViewDelegate>
#property UIWebView *webView;
#end
#implementation MerchViewController
- (instancetype)init
{
self = [super init];
if (self) {
self.navigationItem.title = #"Merchandise";
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIWebView *webView = [[UIWebView alloc] init];
webView.scalesPageToFit = YES;
self.view = webView;
self.webView = webView;
webView.delegate = self;
[self setURL];
}
- (void)updateBackButton {
if ([self.webView canGoBack]) {
{
[self.navigationItem setHidesBackButton:YES animated:NO];
//UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:#"backTickets"] style:UIBarButtonItemStylePlain target:self action:#selector(backWasClicked:)];
UIBarButtonItem *backItem = [[UIBarButtonItem alloc] backButtonWith:#"Back" tintColor:[UIColor orangeColor] target:self andAction:#selector(backWasClicked:)];
backItem.tintColor = [UIColor orangeColor];
[self.navigationItem setLeftBarButtonItem:backItem animated:NO];
}
}
else {
/*
[self.navigationItem setHidesBackButton:YES animated:NO];
//UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:#"backTickets"] style:UIBarButtonItemStylePlain target:self action:#selector(backWasClicked:)];
UIBarButtonItem *backItem = [[UIBarButtonItem alloc] backButtonWith:#"Fan Zone" tintColor:[UIColor orangeColor] target:self andAction:#selector(openMenu:)];
backItem.tintColor = [UIColor orangeColor];
[self.navigationItem setLeftBarButtonItem:backItem animated:NO];
*/
}
}
- (void)webViewDidStartLoad:(UIWebView *)webView {
[self updateBackButton];
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
[self updateBackButton];
[_spinner stopAnimating];
}
- (void)backWasClicked:(id)sender {
if ([self.webView canGoBack]) {
[self.webView goBack];
}
}
- (void)setURL
{
NSURLRequest *req = [NSURLRequest requestWithURL:[NSURL URLWithString:#"https://www.lawlorscustom.com/omaha-lancers-hockey"]];
NSLog(#"loadRequest: %#", req);
[(UIWebView *)self.view loadRequest:req];
}
#end
The "else" portion in "updateBackButton" is commented out because if I don't comment it out, when the view first loads there are two back buttons overlapping.

Answer 1

After struggling for a while, the answer was to do:
[self.navigationItem setHidesBackButton:NO animated:NO];
self.navigationItem.leftBarButtonItem = self.navigationItem.backBarButtonItem;