Mi Account Lock Check
Xiaomi handsets can carry two locks at once — the Android Google account lock and Xiaomi’s own Mi Account binding. This checks the second one, which is the one that catches people out because it survives a reset and nobody mentions it in the listing.
Dial *#06# on the handset to display its IMEI.
This check runs against a live device database. Create a free account to run it.
Takes a moment, and your results are saved to your account.
What the Mi Account binding does
Switching on Find Device in MIUI or HyperOS binds the handset to one Mi Account. From then on a factory reset does not free it: the setup assistant asks for that account, and the binding is checked against Xiaomi’s servers rather than anything stored on the phone.
The reason this trips buyers up more than Apple’s equivalent is that it arrives on top of the ordinary Android lock. Clear the Google account requirement and you can still land on a Mi Account prompt three screens later. They are separate systems, held by separate companies, and each has to be dealt with on its own terms.
Only the account holder can release the binding, and it takes them a minute: sign in at i.mi.com, open the device list, remove the device. Xiaomi will also unbind a handset against genuine proof of purchase through its own support channels. There is no third-party shortcut worth trusting here, and we would rather say so than sell you one.
Brands on the same account system
Make the seller reset it in front of you. A Xiaomi that walks through setup to the home screen with your SIM in it has cleared both locks. Anything short of that — including a phone handed over already on the home screen — leaves you guessing.