Using Xperia with SIM

[SurtseyAna]

I have been happily using my old Xperia T as an MP3 player. Not having a SIM didn't bother it until I unlocked the boot-loader.
Now the phone issues a warning: As there is no SIM the phone surmises that it has been accidentally powered on during shipping and will switch off in 15 minutes.

Any way to fix this?

[Piscie]

Hello @SurtseyAna, I'm afraid it seems a hardware issue which requires physical inspection. But you can try a factory data reset first.

A also came across this link: https://developer.sony.com/develop/open-devices/get-started/unlock-bootloader/