So, my phone went into the water and I bought another one with broken display just to get the motherboard. It came with baseband unknown error. I thought it was a bad software on that board. So I flashed the software mentioned in the first post and after that it had a baseband, single SIM baseband, and after one day, when I turned on again the phone the unknown baseband issue reappeared. Don't know the cause of this. When the baseband was showing I took a photo of imei. Now I tried to flash the software again but the baseband unknown issue doesn't disappear. Thanks very much for the help.