Quick answer
Hand over money only after the phone clears six checks, taken in order. The *#06# number has to match what Settings, the box label and the bill show, and texting KYM <15-digit IMEI> to 14422 must return a clean result. With the seller’s account still on the phone, write down the battery health (plus an iPhone’s repair record) and try every part with your own SIM. Next, the seller removes their Google, Apple or Samsung account and resets the handset as you watch; you then run setup and make sure it never asks for their login. Last comes a receipt they sign, plus a copy of their ID.
Listing photos can’t show what makes a used phone a bad buy: an IMEI that’s been blocked, an account lock belonging to someone else, or a worn-out battery. Each one has a check you can run at the meeting. Once the seller has been paid, every one of them becomes your problem.
The sequence below is deliberate. Some checks need the seller’s account still on the phone, and others only work after it has gone. Whether you’re buying from a stranger, through an online ad or from a shop, the same order applies. The counter notes come from Mobivault, the Bhopal phone shop owned by PhoneSahi’s editor, Lokesh Rathore.
In this article10 topics
- Settle these before you meet the seller
- Check 1: Match the IMEI everywhere, then run KYM
- Check 2: Note the battery’s health before anything gets wiped
- Check 3 (iPhone): Find out which parts have been swapped
- Check 4: Put every part to work with your own SIM and cable
- Check 5: Watch the seller’s account come off, then the reset
- Check 6: Paper first, payment last
- Already paid and something’s wrong?
- More questions before you buy used
- Sources and further reading
Settle these before you meet the seller
- Get the IMEI ahead of time. Ask the seller to send a picture of the label on the box or a screenshot of what *#06# shows. With that, you can run Check 1’s KYM test at home and save yourself a wasted trip if it fails.
- Confirm the bill and the original box come with it.
- Ask if it was bought on EMI. If it was, make sure the loan is fully paid off. When instalments go overdue, a lender can lock the phone remotely; Samsung’s Knox Guard is one tool that does this.
- Make sure the seller can sign in on the spot. Removing their account in front of you needs their password, so they should come prepared.
- Buying an iPhone? Ask the seller to turn off Stolen Device Protection at home. If the iPhone isn’t somewhere it considers familiar, this feature imposes a one-hour delay before the Apple Account can be signed out.
- Pack your SIM card, a charger and a charging cable. If the ad says 5G, carry a SIM you know gets 5G on your current phone. Pick a busy public place with a strong network and Wi-Fi available, since several checks need a connection.
Check 1: Match the IMEI everywhere, then run KYM
The IMEI is the 15-digit number a mobile network uses to recognise a handset, and a dual-SIM phone has two of them. Whether you read it off the screen, Settings, the box or the bill, it must be the same number every time.
| Any phone | Dial *#06# and the IMEI appears straight away; on a dual-SIM handset you’ll see both. |
| iPhone | Scroll towards the end of Settings → General → About. Models from iPhone 6s up to the iPhone 13 series, and iPhone SE (2nd and 3rd generation), have it printed on the SIM tray as well. If the phone was wiped already, the Info button at the lower right of the Hello screen reveals it. |
| Android | Settings → About phone on a Pixel; other makers give this menu their own name. Pixel Help also mentions the SIM tray. |
| Box and bill | On the sticker on the box, and possibly on the invoice. |
- Compare the *#06# result with Settings, the box label and the bill, if the bill lists an IMEI. Not a single digit should differ.
- Send KYM <15-digit IMEI> by SMS to 14422. You can run the same test on the CEIR website’s KYM page (it confirms it’s you with an OTP on your mobile) or in the Sanchar Saathi app under Know genuineness of Your Mobile Handset. A phone with two IMEIs needs both checked.
- Hold the reply up against the handset. CEIR says the reply names the device type, brand, manufacturer and model, and all four should fit the phone in your hand. If any detail is off, or a warning status shows up, don’t pay.
Warning: CEIR tells buyers not to go ahead when KYM reports a handset as Black-listed, duplicate or already in use. Walk away as well if the IMEIs don’t agree, if *#06# shows nothing but zeros or a number that isn’t valid (CEIR says Indian networks don’t permit phones with such IMEIs), or if the seller won’t allow the test.
The government has warned about exactly this. The Department of Telecommunications (DoT) said in December 2025 that it had seen stolen or blacklisted phones being sold again through the country’s big second-hand market, and that a person who buys one becomes an abettor in crime and ends up out of pocket.
From the Mobivault counter: Our rule for customers eyeing a used phone is simple: the IMEI test comes before everything else. Dial *#06#, check the number against the bill and the box, then send it to KYM on 14422. Battery, parts and locks can wait until that result is clean.
Check 2: Note the battery’s health before anything gets wiped
Battery health compares how much charge the battery holds today with what it held when new. Take the reading now, while the phone is still set up, because the reset comes later in this list.
| Handset | What you’ll see | Menu path |
|---|---|---|
| iPhone 14 and earlier | Maximum capacity and peak performance capability | Settings → Battery → Battery Health & Charging |
| iPhone 15 and later | Cycle count and maximum capacity, plus the dates of manufacture and first use | Settings → Battery → Battery Health |
| Pixel 8a and later | A “Normal” or “Reduced” status (Reduced means under 80%), along with estimated capacity and cycle count | Settings → Battery → Battery health, then tap Battery capacity; the cycle count is in Settings → About phone → Battery information |
| Samsung Galaxy | A rating of Normal, Weak or Bad | Samsung Members → Support → Phone diagnostics → Battery status |
- Judging an iPhone: in ideal conditions, an iPhone 14 or older battery is built to hold 80% of its original capacity at 500 full charge cycles. Apple puts the iPhone 15 models’ figure at 1,000 cycles. A message saying “Your battery’s health is significantly degraded” is Apple telling you the battery should be replaced. If you see “Unable to verify this iPhone has a genuine Apple battery”, treat the health numbers as possibly wrong.
- Judging a Pixel: Google’s advice is to replace the battery when capacity falls below 80%, or at a cycle count of 800 for Pixel Fold and for Pixel 3 up to Pixel 8 Pro, or 1,000 for Pixel 8a and later. The Pixel 6a and 7a, the Pixel 7 and 7 Pro, and the Pixel 8 and 8 Pro don’t display any health status.
- Other brands: check Settings → Battery for something like a battery health entry. If nothing’s there, watch how the battery copes while you run the tests in Check 4, and allow for a new one in your offer.
Check 3 (iPhone): Find out which parts have been swapped
If a repaired iPhone has iOS 15.2 or later, an extra section called Parts and Service History shows up in Settings → General → About. Its coverage varies by model: display, battery, logic board, and front and rear cameras from iPhone 12 onwards; display and battery on iPhone 11 models; and just the battery on iPhone XR, XS and XS Max, along with iPhone SE (2nd and 3rd generation). Older iPhones and any other parts aren’t tracked, so if the section is missing, you can’t assume the phone was never fixed.
| Genuine | Genuine Apple parts, fitted using Apple’s processes. |
| Used | This part was previously installed in, or used by, another iPhone. |
| Unknown | Apple couldn’t verify this part; it may not be genuine, or may not work as expected. |
| Unverified | Its logic board came from a different iPhone; Apple Pay and some other features may be affected. |
| Finish Repair | The work was left unfinished. Apple says the part might not perform properly, and the parts need calibrating before Face ID or Touch ID can unlock the phone. |
Check 4: Put every part to work with your own SIM and cable
| Screen | Open an all-white image and then an all-black one to expose dead pixels or lines. Drag an app icon across the whole display to test touch. Google notes that a screen coming away from the body can signal a swollen battery. |
| Frame, edges and buttons | Check the frame for bends and cracks, and the display edges for gaps. Press every button, then test Face ID or the fingerprint reader. |
| Charging port | Your own cable should plug in firmly, with no wobble. |
| Calls and mobile data | Move your SIM through each physical slot in turn. Make a call on the earpiece and again on speaker, and switch mobile data on. |
| 5G | Promised 5G? Stand where your current phone picks up 5G and see whether the 5G icon shows with your SIM in this one. No icon? Our fix for 5G not showing on Jio, Airtel and Vi covers the settings and bands to check. |
| Cameras | Every rear lens and the front camera, for photos and for video, focus and flash included. |
| Everything left | Location, Bluetooth, Wi-Fi, vibration, the loudspeaker and the microphone. |
| Samsung shortcut | In Phone diagnostics, tap Test all. The tests vary by model and can include the buttons, camera, mic, speaker, touch screen, SIM card and official software. |
From the Mobivault counter: Of all the used phones customers have brought to us, two hidden faults come up repeatedly: a replacement screen that’s not an original part, and a weak or swollen battery. Warning signs are odd colours, patchy touch response and uneven brightness. Note the battery health number, and check if the back panel or display has begun lifting.
Check 5: Watch the seller’s account come off, then the reset
iPhones have Activation Lock and Android phones have Factory Reset Protection (FRP). Both bind the handset to the last owner’s account, and neither is cleared by erasing the phone remotely or resetting it from recovery mode. After that kind of wipe, the handset demands the previous owner’s account password, or the passcode or screen lock it had before. The lock has to be gone before you pay.
iPhone: getting Activation Lock released
Apple tells buyers not to take ownership of a second-hand iPhone that Activation Lock still protects. No website can confirm it for you either: in January 2017 Apple retired the iCloud.com tool that looked up lock status from an IMEI or serial number, and it now says the check has to be done on the device itself.
- Checks 1 to 3 must be finished first, while the account is still on the phone.
- On iOS 26 or later, the seller signs out at Settings → [their name] → Sign Out and then chooses Erase this iPhone. Before iOS 26, signing out comes first, followed by Settings → General → Transfer or Reset iPhone → Erase All Content and Settings. They may be asked for their Apple Account password.
- Turn the iPhone on. If it shows iPhone Locked to Owner (iOS 15 onwards), the lock is still in place.
- Run through setup on your own. If it wants an Apple Account login that isn’t yours, pass the phone back so the seller can enter their password.
- Once the Hello screen appears, the iPhone is clear and you can set it up as your own.
A seller who can’t meet you can still free the iPhone remotely. On icloud.com/find in any browser, they choose the device and then Remove This Device.
Android: switching off FRP (and the Samsung account)
FRP rides on the Google account. Google explains that it comes on when an owner adds a Google account and sets a screen lock, and goes off when that account is removed. Reset such a phone remotely or via recovery mode and it won’t finish setup until someone enters its previous screen lock or signs in with a Google account previously synced with it. Without either, Google warns, the device is unusable.
- Every Google account has to come off. The seller opens Settings → Passwords & accounts (on other phones the menu may be Manage accounts, Users & accounts or Passwords, passkeys & accounts; on Samsung, it’s Accounts and backup → Manage accounts), taps each account and chooses Remove account.
- Galaxy phones need one more step: signing out of the Samsung account at Settings → Samsung account → Sign out. According to Samsung, this turns off Find My Mobile, and menu names vary with the model and software version.
- Then they factory-reset the phone from Settings. On Samsung, that’s Settings → General management → Reset → Factory data reset.
- Join a Wi-Fi network and do the setup yourself. Any prompt for the old owner’s screen lock or one of their accounts (a Google one, or a Samsung one on a Galaxy) means a lock remains, so don’t pay.
Warning: Skip any listing that says “works on Wi-Fi only”, “FRP bypassed” or “iCloud locked”. Those locks live in the old owner’s account, and lifting them properly means going through that account.
Check 6: Paper first, payment last
- The bill: any IMEI printed on it must match the phone. A bill in a third person’s name means you should ask how the seller came to have the phone.
- Their ID: check an original government-issued ID and keep a copy of it.
- A receipt you both sign: it should record the seller’s name and address, their mobile and ID numbers, the model, both IMEIs, the date, the price and the payment method, plus a statement that the phone is the seller’s own, with no loan pending and no account lock on it.
- Keep the lot: box, bill and receipt. If the phone is ever lost or stolen, the invoice can be used on CEIR’s blocking form.
Tip: Pay at the very end, by UPI or bank transfer, which leaves a record. Once you’ve paid, only the seller can get a lock lifted for you. Apple’s support route for Activation Lock asks for proof of purchase; whether a private seller’s receipt qualifies, Apple doesn’t say.
Already paid and something’s wrong?
| What you notice | What it means | What to do |
|---|---|---|
| An Activation Lock screen on the iPhone | It is still tied to the seller’s Apple Account | Contact the seller: on icloud.com/find, they can choose the device and tap Remove This Device. |
| Android setup asks for the previous owner’s Google account | FRP hasn’t been switched off | The way through is a Google account it was synced with earlier, or the screen lock it had before. That means the seller has to sign in, or type that lock, on the handset. |
| CEIR shows the IMEI as blocked | Per CEIR, a blocked handset can’t be used on any Indian network, and it’s the owner who unblocks it, after letting the police know it’s been found. | Start with the seller, receipt in hand. If that fails, go to your local police station and bring the handset, your receipt and what you know about the seller. For background, read our guide to blocking a lost phone on CEIR and unblocking it later. |
| Someone offers to “fix” it by changing the IMEI | Per CEIR, nobody except the manufacturer may lawfully alter an IMEI | Refuse. |
At Mobivault, customers who discover that a used phone they bought is locked or blocked get our help taking it, bill in hand, to an authorised service centre for that brand.
Our verdict
- Walk away if KYM flags the IMEI, the numbers disagree, setup still wants the seller’s login, the listing says “iCloud locked” or “FRP bypassed”, or the seller blocks any of these checks.
- Bargain if battery health is below 80%, or if there’s no reading to go on: allow for a replacement battery in your offer.
- Pay only once everything else has passed and the receipt is signed, and do it by UPI or bank transfer.
More questions before you buy used
Can I find out online whether an iPhone is iCloud-locked?
Not any more. Apple retired its web-based Activation Lock check in early 2017, so the test has to happen on the handset: you shouldn’t see an “iPhone Locked to Owner” message, and setup shouldn’t ask for an Apple Account other than yours.
Won’t a factory reset clear the lock anyway?
Not on its own. A remote erase can leave an iPhone Activation Locked. Erasing it through the phone’s own Settings does clear the lock, but the owner needs their Apple Account password for that when Find My is switched on. On Android, a phone wiped remotely or from recovery mode will demand a Google account previously synced with it, or its earlier screen lock. So the safe sequence is: the seller removes their account, resets the phone in front of you, and you handle setup.
KYM came back clean. Can I skip the rest?
No. KYM checks the IMEI against CEIR’s records and nothing more. It can’t tell you anything about Activation Lock, FRP, the battery’s condition or past repairs.
How low a battery health figure is too low?
It varies by phone, so there’s no universal cut-off. Google recommends replacing a Pixel’s battery when its capacity is below 80%. Apple’s design target for iPhone 14 and older is 80% after 500 cycles in ideal conditions, rising to 1,000 cycles on iPhone 15 models. If you see a figure under 80%, include a new battery in what you offer.
The seller can’t find the bill. Should I still buy?
It’s riskier. With no bill, nothing ties the IMEI to an actual sale, and proof of purchase is what Apple’s Activation Lock help asks for. If you still want the phone, three things become non-negotiable: KYM must be clean, the reset must happen while you watch, and the seller must sign a receipt and hand over a copy of their ID.
Sources and further reading
- Sanchar Saathi CEIR portal: KYM help, IMEI FAQs and blocking a phone
- CEIR’s Know Your Mobile (KYM) genuineness test
- DoT warning on resold stolen and blacklisted phones (PIB, 1 December 2025)
- Sanchar Saathi app on Google Play
- Apple Support: Activation Lock explained for iPhone and iPad users
- Apple Support: getting Activation Lock removed
- Apple Support: preparing an iPhone or iPad to sell, give away or trade in
- Apple Support: what Stolen Device Protection does
- Apple Support: where an iPhone shows its IMEI and serial number
- Apple Support: reading Parts and Service History
- Apple Support: iPhone battery health and performance
- iPhone User Guide: viewing battery health and usage
- Apple drops its online Activation Lock check: iPhone in Canada report, January 2017
- Android Help: protecting your phone from unauthorised use
- Android Help: how to add or remove an account
- Pixel Help: locating your Pixel’s IMEI
- Pixel Help: understanding your Pixel’s battery
- Samsung India: erasing your personal data from a Galaxy
- Samsung India: how to deactivate Find My Mobile
- Samsung India: Galaxy battery status check
- Samsung US: running diagnostics on a Galaxy
- Samsung Knox Guard documentation for administrators
- Samsung Australia: Galaxy factory reset and FRP
