Even with a lock app on an installment phone, one question always comes up: "What if the customer factory resets the phone from recovery mode?" You can block reset from Settings, but a reset from recovery mode by pressing the power and volume buttons — no app can stop that. This is where FRP comes in.
What is FRP (Factory Reset Protection)?
FRP is Android's own security feature. If a phone is reset without authorisation while a Google (Gmail) account is signed in on it, then after the reset the phone will ask for that previous Google account's email and password to start up. Without the correct account, the phone's setup won't finish — meaning the phone can't be used.
Why FRP is a must on installment phones
Suppose the customer stops paying and resets the phone from recovery mode. The lock app is indeed wiped, but if FRP is on, the phone will ask for the shop's Gmail to start up. The customer doesn't know it, so the phone stays unusable — they have to come to the shop.
The right method for a shop
- Create a separate Gmail for the shop — only for installment phones. Don't use a personal Gmail.
- When setting up the phone at the time of sale, sign in with this Gmail.
- Keep the password safe — only the owner or one trusted person should know it.
- When releasing the phone after the installments are finished, remove the shop's Gmail so the customer can add their own account.
Our support team explains how to do this during setup in PhoneSell Pro. A simple explanation of how the lock works: how an EMI phone lock works.
Device Owner + FRP — two layers of security
| Layer | What it blocks |
|---|---|
| Device Owner lock (QR setup) | Reset from Settings, deleting the app, turning off the lock |
| FRP (the shop's Gmail) | Using the phone after a reset from recovery mode |
With both together, the installment phone effectively stays under your control. Details: Device Locker.
A few precautions
- Not a different Gmail for each phone — keeping the same shop Gmail on all of a shop's phones makes it easier to manage.
- If 2-step verification is on for the Gmail, signing in after a reset may need an OTP — put the shop's phone number there.
- Tell the customer clearly from the start that the shop's security will stay on the phone until the installments are finished — this avoids misunderstandings later.
Final word
FRP is not separate software — it is Android's own feature. Used correctly, it closes the biggest loophole on installment phones. Use it together with PhoneSell Pro Device Locker, and learn about the other risks of installment sales too.
