I downloaded the code and ran the sample, and there are no rounded corners present in the spinner provided by the original code.
I notice in your image that your view containing the spinner also has rounded corners? Are you using layer-backed views with the setCornerRadius:
method?
If so, it looks like the spinner sub-view also has that property set, as it does looks like the spinner and your containing view have the same size rounded corners.
Try specifically setting the corner radius of the spinner view to 0?