This problem may happen if you power off the MiFi when it is flashing. It is beyond repair. Maybe you could contact your dealer for a replacement if it is within the warranty.

Thank you for the reply.

Well, maybe. As far as I remember, I never tried to flash it up.

It was suddenly turned off. I try to it back on, it turns up like this.

In the end, I sent it back to TP-Link and I got a new device as a replacement with an upgraded version (3.2, was 3.0)

Hi cecikut,

i have exactly the same, on day, after turning on, it stuck in showing "TP-Link" logo screen. The day before it worked and i did not flash it or try other things with it.
Did you just sent the device back to TP? Was it still in warrenty? Anything else provided, or easy straight-forward process?