File | Nokia 24 Nvram
to create a backup of your current NVRAM partition. This is the only way to ensure you can restore your original IMEI if things go wrong. Fixing "Invalid IMEI" (Software Solution)
: Connect the device in "VROM" mode (typically powered off without holding buttons, or using specific volume combinations) and click 'Download'. nokia 24 nvram file
The phone shows "Invalid" or "0" when dialing *#06# . to create a backup of your current NVRAM partition