SUPEE-9767 v2 causes saveBilling() 500 server error

[Ericclay]

 Hello All,

 I'm having an issue that seems to be different then most with this 9767 v2 Patch.  The patch applied without trouble and I cleared the cache and the java/css cache.

When I go to checkout (onepage) when I continue from the shipping address to move to selecting shipping options the website jumps back to a cart page.  I never see shipping options.

I DO NOT HAVE a theme that overrides the checkout process. (no from key stuff to add)

Turning OFF the formkey requirement in the admin section has NO EFFECT.

See below for update.

Thanks again!

Eric

[Ericclay]

 *** Update ***

 So the problem seems to be saveBilling() is returning 500 server error on checkout.  I have no clue why that is.  When I look at the form data from the actual call there is a FORMKEY value there. So a formkey issue doesn't seem to be related to that.

I did notice one item.. The patch which applied to my 1.9.2.3 webpage has a different

/app/code/core/mage/sales/model/quote/Item.php

then the 1.9.3.4 version.. Why is that?

1.9.2.3 Patched Code inside Item.php in compare( function)

                            unset($itemOptionValue['qty'], $itemOptionValue['uenc']);
                            unset($optionValue['qty'], $optionValue['uenc']);

1.9.3.4 Code is

                            foreach (array('qty', 'uenc', 'form_key') as $key) {
                                unset($itemOptionValue[$key], $optionValue[$key]);
                            }

I don't know if this is related to my problem but it was something I noticed.

Any thoughts or suggestions would be greatly appreciated.  I'm about to give up on the patch if I can't make any progress here.

[Ericclay]

 I've chased my problem down to the following.

Call to undefined method Mage_Checkout_OnepageController::isFormkeyValidationOnCheckoutEnabled()

Where is that function suppose to be defined?  I downloaded a new install of 1.9.3.4 and I couldn't find it in that code either.

[Ericclay]

Solution Follows

app\code\core\Mage\Core\Controller\Front\Action.php

was being overwritten at

app\code\community\Mage\Core\Controller\Front\Action.php

This old code was taking precedent over the patched Action.php which includes the new function isFormkeyValidationOnChecko‌utEnabled(); and some other stuff.

In my case two solutions where available.

Solution 1: After inspecting the old Action.php it was found that this file was not required and simply deleting this file allowed the new version of Action.php to take over.

Solution 2: Was to copy the function isFormkeyValidationOnChecko‌utEnabled() and every other change made to Action.php over to the old Action.php to preserve any special behavior the template included in the first place.