If you’ve been using Android tablets for a while, you’re probably a fan of the way they’ve been effectively the opposite of Apple’s walled garden. Based on open-source software, effectively anybody could make an Android phone tablet, and any Android device could have the Play Store sideloaded onto it—even the Amazon Fire.

But some Android users have discovered that just changed.

While the open-source Android OS can be put on anything without needing permission from Google, Google’s suite of apps—the Play Store, Gmail, Google Maps, Hangouts, etc.—are licensed to device makers under license terms that require them to be implemented a certain way. Up until now, Google hasn’t done anything about non-compliant devices with the Play Store on them—meaning that users could sideload them after the fact (or fly-by-night hardware manufacturers could disregard Google’s license terms and throw those apps on anyway).

But starting March 16th, Google began blocking installation of the Play Store onto non-certified devices with firmware build dates after March 16th. Attempting to log into Google to install the Play Store will fail with an error message stating that the device is not certified by Google.

If you want to see if your device is affected, go into the Play Store app, tap the hamburger to open the menu, then choose “Settings” and scroll down to the “About” section. There should be a listing there for certification status, which will either say “Certified” or “Uncertified.” If it’s “Uncertified,” then your days of accessing the Play Store from that device are numbered.

This has the potential to affect not only Fire users, and people with cheap Chinese tablets (like the Teclast Kindow) that couldn’t possibly have gone through Google’s certification program (Google’s apps are blocked in China), but also any of those Android power-users who like to install customized ROMs, including Cyanogenmod.

It may also affect any number of one-off or customized Android devices, such as GoodEReader’s crowdfunded e-ink tablet, or even the $800 Onyx Boox Max 2 I reviewed the other day. (The Boox Max 2 doesn’t ship with all the Google apps installed, as Google’s license requires, and it seems to use a customized version of the Play Store which omits the certification status entry from its settings screen altogether.)

Working Around the Restriction

Fortunately, Google is including a workaround for custom ROM users (and, presumably, individual users of Fire and cheap Chinese devices). It has set up a device registration page where custom ROM users can register their devices using the GSF (Google Services Framework) Device ID, a device identification number that’s newly generated on any factory reset and reinstallation of Google Play Services.

(Or, at least, they’re supposed to be able to do that. At the time the article was written, the page was not accepting GSFs, but was accepting IMEIs—which only phones or cellular-connected tablets have, not wifi-only tablets. According to an Android Police writer who spoke to Google, this is a mistake, and the site will accept GSFs when it is “ready to go.” Whenever that might be.)

Update: It turns out the issue with the site was that you were supposed to convert the GSF ID into decimal format. See updated instructions below.

The site only allows you to register 100 codes per Google account—presumably to keep device manufacturers from doing it. Since you’ll get a new GSF each time you factory reset, you might use those up sooner or later. It’s not clear whether there’s any way to delete old GSF numbers, though apparently there are ways to hack Android devices into reusing specific GSF numbers.

This change will not affect Amazon Fire tablets just yet, or Android devices with firmware older than March 16th, but the clock is ticking—the next time they get a firmware update, that will bump their build date past March 16th, which in turn means they will stop working. If you have a Fire, or some other uncertified Android device, that’s working with the Play Store right now, here are steps you might want to follow to be prepared for the next update that makes the Play Store stop working.

Registering Your Device With Google

First, install a good Device ID app. Android Police, and I, recommend the one made by Evozi. You can snag it from the Play Store right now, or from APK Mirror if you’re reading this at some point in the future when your device has already stopped logging in. If you can still hit the Play Store, you might want to go ahead and do that now.

If you’re in the process of installing the Google apps onto your Fire, you might want to go ahead and snag this app at the same time you grab the Google packages from APK Mirror.

There are other ways to retrieve your GSF ID, but they tend to require various highly-technical methods like installing certain debugging packages and connecting to your computer with a USB cable. If you want to do that, the XDA Developers board, Android Police, or other such sites can probably tell you how—but the simplest way is just to get the app.

Next, run the app and copy your GSF Device ID. Remember that you need to have installed Google Play Services already in order to get a GSF ID—so if you’re installing those apps on a freshly reset Fire, you need to put Play Services on there first.

If you’ve got Play Services and Evozi’s Device ID app installed, run Device ID, then long-press on the second section down that says “Google Service Framework (GSF)”. Choose the option that says “Copy.” Or, if you want to do this from your desktop, you can just have that panel open and get ready to type in the long alphanumeric string you see. Either way, you’ll need it for the next step.

Convert the GSF ID from hexadecimal to decimal format. Yes, I’m serious. Apparently Google didn’t think the registration process was complicated enough, so they require you to convert this device ID from the hexadecimal format it originally comes in into a decimal format in order to be able to register it. The easiest way to do that is using this online conversion tool. Just paste or type the number you got in the previous step into the field marked “Enter hex number,” click “Convert,” then copy and paste the long number from the next field.

Finally, go to the Google Device Registration page. Make sure your web browser is logged into Google from the same account you’re using to administer your Android device, then enter the reconverted number you copied in the previous step. I’ve tested it with my own devices and can confirm that it does work now.

Once the device is registered, you should be good to go—at least until the next time you need to factory-reset the device, or you buy another uncertified one. You might want to bookmark this post for future reference.

Other Alternatives

If you still can’t get the Google Play store to work, one alternative you might try is Galaxy, a material design fork of the Yalp Store which mirrors apps from Google Play. Bear in mind that using this app does violate §3.3 of Google Play Terms of Service—but then, so do many other methods of downloading Android apps (such as APK Mirror), and the Yalp developers have never heard of anyone’s account being disabled from it.

There are also methods of rooting some Android devices that disable the way Google checks to see whether or not they’re certified—but those are way over my pay-grade for device hacking, so use at your own risk. These and other methods will be discussed at the XDA Developers forum, Android Police, and other technical sites.