I upgraded my Raspberry Pi to a newer kernel and updated the firmware with the following commands:

sudo apt-get update && sudo apt-get upgrade
sudo rpi-update
sudo reboot

After this my pilight couldn’t send anymore using the lirc_rpi module. Al lot of resources mentioned a new device tree and stuff, so I added the following to my /boot/config.txt file:

# Uncomment this to enable the lirc-rpi module
dtoverlay=lirc-rpi,gpio_out_pin=22,gpio_in_pin=18

This caused the lirc_rpi module to be loaded and I could receive data using the pilight-raw command. But sending still wouldn’t work.

After lots of time and effort I found the culprit. The new module seems to have enable softcarrier by default. Also autosensing didn’t work always as intended. So I changed the lines in my /boot/config.txt to the following:

# Uncomment this to enable the lirc-rpi module
dtoverlay=lirc-rpi,gpio_out_pin=22,gpio_in_pin=18,sense=0,softcarrier=off

Now everything works as expected!

Please let me know if this helped you to solve your problem.