Switching to Google Project Fi

My migration to Google Project Fi is complete. Fi is a cellular service plan that uses the T-Mobile and Sprint networks in the USA and others in other countries.

• date: May/June 2016
• from: T-Mobile Lumia 435 (Windows Phone 8.1) with T-Mobile prepaid smartphone plan
• to: Google Nexus 5X (Android 6) with Project Fi plan (which also uses the T-Mobile network; or the Sprint one, but see below)
• while not breaking: my Google Voice number and ability to use it on my phone

I got T-Mobile to unlock my previous phone, T-Mobile Lumia 435 (Windows Phone 8.1) before transferring service. Since the account was T-Mobile prepaid, there is not a web interface to do it. You:

• look up your phone number and IMEI in the phone settings
• LiveChat to T-Mobile to ask to unlock it
• when they ask why, say you have ordered a new phone and want to unlock the old one to increase your flexibility about what you do with it
• hope they say it's eligible; give them an email to send the unlock code to. They say the email will arrive within 24 hours.
• it didn't work the first time, so LiveChat them again a few days later saying I didn't get the unlock email and already checked my spam folder. This time the email does go through, and also the LiveChat agent pasted the unlock code into the chat for me just in case the emailing had a problem again
• google how to enter the unlock code in my phone, because the instructions in the email were all wrong for this device. At least on this particular phone+carrier, go to the phone dialer, enter ##7820#, and then enter the 20 digit unlock code in the screen that comes up. Double check for typoes before submitting the unlock code, because apparently if you typo too many times in a row then the device becomes impossible to unlock. You can return to this ##7820# screen any time later to double-check that the device is unlocked.
• this does not change the OS, so T-Mobile's lack of upgrading Lumia 435 devices to Windows 10 still affects the phone. In fact, since the phone will not be on T-Mobile at all anymore, it may not be able to get the Windows 10 upgrade if T-Mobile offers it. Then again, the phone's Fi data service will be on the T-Mobile network, so who knows. In any event, I suspect T-Mobile is never going to do that upgrade, even though Microsoft — at least publicly — wants them to.

I decided what to do with my phone numbers. I moved the T-Mobile one to Fi on one google account, and kept my Google Voice number on a separate google account.

• They need to be separate accounts. Usually there is at most one Google-provided phone number per Google account. It is possible to accidentally delete your Google Voice number if you migrate a different phone number to an account that had Google Voice while activating Project Fi.
• Forwarding from Google Voice to Project Fi does not work. Google Voice works fine in the Hangouts app on a Project Fi phone. Note that call quality may be different between Fi and Voice, because Fi might use CDMA/GSM/VoLTE while Hangouts Dialer calls will definitely only use regular mobile data and/or WiFi. When I say "different" call quality, I am carefully not specifying which one's call quality will be better (it varied based on some factors). Also, calls over mobile data won't be free with Hangouts Dialer, though the effective rate is pretty cheap.
• I can answer calls to both Fi and Voice numbers on my laptop if I have two hangouts.google.com tabs open, each already switched to the applicable Google account.
• The old Google Voice android app didn't seem to set up properly on this Nexus 5X even though this app had been working okay for texting on the Nexus 7. I think the app is designed to do something special on phones but not tablets, something that doesn't work on Fi phones. So I converted the Google Voice account to Hangouts-based texting. A downside of Hangouts-based texting is I can't get texts and voicemail transcriptions emailed to me.
• This keeps life interesting.
• Keeping Fi and Voice numbers separate means my long-lived Google Voice account is less likely to lose its Voice powers if I stop paying for Fi and something goes wrong with the number's reversion back from Fi to Google Voice. This is supposed to work seamlessly, but I'm pretty attached to my Google Voice number and don't want to risk that. (Given that I have no way to test that reversion, and that it might work differently in the future or in particular circumstances of how my Fi service would terminate.)

Nexus 5X (ordered as part of signing up for Project Fi)

• Since I already had a decently set up Nexus 7 (2013 Wi-Fi "flo"), I used Android's "Set up nearby device" feature to transfer the accounts/data from that device. Both devices were current Android Marshmallow. It mostly worked. Some of the data did not go through, I think because I did not have the "Backup & reset → Back up my data" setting on in the Nexus 7. I think that is the only way the "Set up nearby device" feature has to transfer some kinds of data. My guess is this is why I got an obtuse error message at the end of the Nexus 5X setup process "No backups available for source device". Ways Google can improve: detect and provide useful error messages when backups are off. Or make it work even when backups are off (without sending that data to Google servers in a way that is readable to Google). Also, wishlist: allow Android's backup feature to optionally use a separate encryption password, like Chrome Sync has as an option. If it gains this feature then I will likely start using it.
• Phone case ordered and installed because this phone is thinner and bigger than my previous phones and therefore more likely to get screen cracks or touchscreen wonkiness from skew/dropping. I judged "more likely" from my experience of two touchscreen phones, a tablet, an ebook reader, a chromebook flip, a flip phone, and a sansa clip. So far, all the devices with screens over 4" had issues eventually if I carried them in my bag without protection. All the ones with smaller screens were basically indestructible even in the harsh environment of my bag, without protective cases. I also bought the $5/month breakage insurance for now, while I learn how vulnerable this phone is.
• MIFARE Classic transit card (CharlieCard) put inside the case. It is visible since it is a clear case. This allows me to tell which phone is mine despite the fact that I have the most popular Nexus with the most popular-on-Amazon case for it. Alternatively, I can add stickers to identify it. NFC turned off in phone settings because it interferes with using the MIFARE card. The MIFARE card is still slightly finicky to use while inside the case, so I might have to stop keeping it in my phone case. Sadly, MBTA MIFARE is encrypted so I can't use my phone's NFC as my transit card. (Well, there might be a dubiously legal way to do it. It doesn't sound very technically practical even if possible.) I presume that the MIFARE card would also interfere with trying to use the phone's NFC for anything, such as Android Pay (Android Pay works all the same places that Apple Pay and contactless credit cards do, because they all use the same protocol for talking to the payment terminal. Samsung Pay is different.)
• My email address added to lock screen in case I lose the phone and someone finds it and wants to return it to me. (Not my phone number, because in that situation I'll have lost my phone.) Since people might not know how to charge out-of-battery USB-C devices to see that message, I might want to put my contact info on a physical sticker too for this purpose.
• Pair of microUSB-port-to-USB-C adapters ordered. Made and sold by Anker (on Amazon) and reviewed by Benson Leung to be spec-compliant. These are important because there are a lot of non-compliant USB-C connectors out there that will damage your phone/macbook or just work badly. I put one adapter my bag so that I can use friends' microUSB chargers to charge my phone. I left one at home as a spare, and so that I can use existing microUSB cables to connect my phone to my computer if I want to. (This connection would be at a USB 2.0 data rate. I could get a USB 3 USB-A to USB-C cable if I ever need a higher data rate on that.)
• Cellular phone number migrated from T-Mobile prepaid. I did this several days after activating Fi for data service. The data service worked fine even before migrating the phone number. Logging into my.t-mobile.com with my usual email/password stopped working as soon as I migrated my phone number away from it. Likewise, the mobile data via the T-Mobile SIM in the old phone stopped working as soon as I migrated the number. I imagine the remaining few cents of prepaid value disappeared into the ether (also known as T-Mobile's coffers).
• I forced the phone to use only the T-Mobile network because Sprint's CDMA voice calls were super low quality and T-Mobile's GSM/VoLTE was fine. Others have experienced this too. Sprint does not have VoLTE. (Apparently VoLTE works better on GSM networks anyway because it is possible to fall back from VoLTE to GSM during a call if LTE service disappears, but not possible to fall back to CDMA.) Hangouts Dialer calls on either network are also better quality than Sprint CDMA calls (though they cost mobile data if not on wifi). For context, I live in a city where both T-Mobile and Sprint have good LTE. Dial *#*#34866#*#* to force T-Mobile, *#*#342886#*#* to undo that, etc (more codes). Or use a helpful app like Fi Switch to make entering those codes more convenient.

Fi data SIMs acquired for two old phones.

• They are free NanoSIM cards. You can only order them after activating Fi service. If you want two, you have to request each individually and they will ship in separate envelopes. Free shipping unless you want to pay to get them faster (pay separately for each SIM).
• I already had adapters for NanoSIM to MicroSIM and MiniSIM from my previous migration from ZTE Open C to Lumia 435 in which I kept my T-Mobile plan.
• As expected, GSM calls/texts are not supported over data-only service.
• After inserting the first data SIM, go to https://fi.google.com/account#plan and rename it from "Data-only SIM" before inserting the next one so that you can tell which is which in Project Fi's data usage breakdown. (I did not do this, so I had to guesstimate which is which based on order and/or data usage.)
• FirefoxOS ZTE Open C works perfectly with the data SIM. Insert SIM then go into Settings → Cellular & Data → {Data settings, Message settings, A-GPS settings} and set each of them to "(custom settings)", APN: h2g2. Then reboot for good measure.
• Unlocked T-Mobile Lumia 435 Windows Phone 8.1 works except for tethering. Insert SIM, boot, it will ask you what network profile to treat this new SIM as; pick T-Mobile.
• https://fi.google.com/account has a nice overview of data usage per device over time, but it does not appear to update in real time when I use data. I haven't figured out the details of when and how quickly it updates.
• Note that if you are multiple-logged-in to Google in your browser, and your Fi account is not the first login, then you'll need to edit the above URLs to have ?u=2 at the end of the URL before the #, where "2" is whichever number shows up in your URLs if you go to https://fi.google.com/ and select the Fi account.

Even though Project Fi is sort of prepaid, they bill you for any data overages rather than cut off your data, and they require you to keep a credit card on file with them (Google Play gift cards do not work as payment for Project Fi). This is a step down from T-Mobile prepaid, who will helpfully throttle/stop your service rather than risk putting you in $10k of debt (a thing that some postpaid plans notoriously make possible). There is a way to set a data limit but it appears to be an Android feature. Data-SIM devices may not support that, there's probably no way to make the limit be per-Fi-account rather than per-SIM, and anyone who hacks or borrows your phone can change the limit to whatever they want.