How to de-Fi your iPhone

by Colin Berkshire

I have a new iPhone 12 Pro Max. The main selling feature for me was the dual-SIM capability. I travel internationally a lot (Or, I did before we went into mass-hysteria mode.) So having my main SIM and a local country SIM is a big deal for me.

I decided to try Google Fi. It was not a good experience, AND it hosed/partly-bricked my new iPhone.

Let start with how to un-brick your iPhone if you try Google Fi:

There is a bug in Apple’s software that is quite serious: If you use a SIM that requires you to edit the APN settings, then removal of that SIM will permanently partially brick your iPhone. By “partially brick” I mean that when you install another SIM, like Verizon’s, many capabilities will fail to work (like being able to send any picture via SMS. You may also experience frequent call failures and other problems.

The problem is that using a Google Fi SIM in your iPhone requires that you edit the APN settings. Removing the Google Fi SIM from your phone (such as to use a different SIM) leaves those APN settings in place, but they become unviewable and uneditable. The new (non-Google-Fi) SIM then will continue to use Google’s APN settings and you cannot edit those settings, cannot delete them, and cannot even know they are there, hidden. Worse, doing a “Reset Network Settings” on your iPhone will not clear the hidden APN settings. So your phone is permanently partially bricked.

The solution is to find that Google Fi SIM that you chucked in the trashcan. Put it back into your iPhone. Now, go to the APN settings and click the red link to remove them. Confirm. Now, the rogue APN settings are gone and you can install your Verizon or other SIM and it will work again.

This is a terrible bug because you cannot see the rogue APN setting when your Verizon (or other carrier) SIM is installed. You cannot edit it, you cannot delete it. So there is no possible way to know what the problem is. Worse, you need that Google SIM in order to re-expose the APN settings so that you can delete them.

In discovering this bug I spent hours on the phone with Apple tech support. They knew nothing about this but or the resolution. I finally figured it out for them. I tried to get the support rep to document the problem nd pass it to the engineers…but Apple has become such a huge company that I don’t know that it is possible for any Apple employee to report a serious bug. (I once reported a bug in Apple iPhone’s calculator that would show the result of 1+1+1 being 27, and other similarly stupid math errors. Despite sending this to Tim Cook’s office it took Apple over six months to correct the problem.)

The moral of this story is that iPhone users must keep their Google Fi SIM. You will need it if you ever discontinue service. And, you must remember to delete the custom APN while the Google-Fi SIM is installed.