I just found the solution ... I boot on an nfs server. I just transferred the files from the / boot folder to my SD card. no problem with the RFLink module after reboot Thank you again for your help ! For information, on RPI4 the way to the USB port is /dev/serial/by-id/usb-Arduino__www.arduino.cc ...

Thanks for help... But the manipulations do not work pi@raspberrypi:~ $ sudo modprobe ftdi_sio modprobe: ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file '/lib/modules/4.19.58-v7l+/modules.dep.bin' modprobe: FATAL: Module ftdi_sio not found in directory /lib/modules/4 ...

Thanks for your help :-) This command return : pi@raspberrypi:~ $ dmesg |tail [ 9.841022] random: crng init done [ 9.841036] random: 7 urandom warning(s) missed due to ratelimiting [ 12.494954] uart-pl011 fe201000.serial: no DMA platform data [ 12.927777] Adding 102396k swap on /var/swap. Priority ...

Hello everyone, (Sorry... Google translate :D ) It's been 3 years since I was running with RFlink without any problem. But since September 2, impossible to communicate with the arduino! (I changed the USB cable and even the arduino in doubt) on a Raspberry 4 with raspbian above But nothing works! In ...