Lenovo K920 (vibe z2 pro) Baseband version: unknown

Hi, i have (or i had :crying:) a lenovo k920 (chinese version) i have installed via qfil a modded row rom. After that it won't read sim cards anymore (it show only two red cross). by typing on the dialer *#06# i sow that both IMEI was lost (both value was 0) so i replaced the right ones with a little software found on the net. It still won't read sim cards and i noticed that in "version information" it show Baseband version: unknown.
I have done anything: reinstall modded rom, back to stock rom, try another rom...but nothing changed. Please someone can help me?
ty and sory for my English.