[Support Thread]SM-G906K baseband unknown, auto reboot after power on for a while

Help, Help, Help

Problem: SM-G906K baseband unknown, auto reboot after power on for a while
what I tried:
I flashed serverl custom roms and samsung firmwares.
After the last time firmware flash, it reported baseband unknown, and can't register network, and auto reboot a moment later.
I have no back up (efs and etc.) unluckyly.

Thank you all for giving any help
Best Regards