BPI-R4 serial connection problems

Hi, now I have a problem and a question. I’m trying to get Openwrt onto the BPI-R4 with an SD card. I have the problem that I can establish a connection via Putty, I can also see the boot process, but I cannot make any entries. Consequently, I cannot start the installation in the NAND memory. It always worked the last time. I have also tried another program, same problem. What am I doing wrong?

which uart adapter do you use? for r3/r4 ftdi is recommended…be aware that 5v ttl may damage the soc (you can measure from gnd to tx with multimeter)

I use a MiniUSB to serial adapter that can be configured for 5V or 3.3V. I have configured it for 3.3V. As I wrote before, I can follow the boot process in the terminal, but I can’t select anything…

edit problem solved

How? What have you done?

The cable between FTDI and BPI was defective, I replaced it -.-