The reason for iPhone 4 and earlier only isn't the slow speed of the process but the fact the newer models include a Qualcomm chip so the patent exhaustion prin

The reason for iPhone 4 and earlier only isn't the slow speed of the process but the fact the newer models include a Qualcomm chip so the patent exhaustion principle comes into place as Qualcomm has a license from Samsung. I believe if this wasn't the case the import ban would also apply to the newer models.