: In many jurisdictions, including the US and UK, it is illegal to change a device's IMEI to misrepresent its identity or unblock a stolen phone.
Most MT6580 phones max out at Android 7.0. If you have a custom Android 8/9 ROM (like LineageOS 15.1), the AT command still works if the kernel has the pttycmd interface. Otherwise, use SN Writer.
: Open your phone's dialer and enter *#*#3646633#*#* to enter MTK Engineering Mode .
: On many MediaTek devices, you can access the hidden menu by dialing *#*#3646633#*#* .