I have discovered today using the internet4 APN is resulting in packet corruption. Over the last couple of days I have been trying to update the firmware of my ps3 and ps4 over wireless via a 4g router (315s). Every time the playstation reported cuppupted file after the firmware download completed. I tried everything and nothing helped. After changing the APN from 'internet4' to 'internet' the problem solved itsself. Changing back to internet4 reproduced the issue.
Are you arare of this fault and have an ETA as to when it will be fixed?