Affects Pi4 only
If you have a Pi4 and are using a RTL-SDR dongle without any data flow, this could be a problem with the Pi4 kernel and not the FR24 feeder itself.
You can confirm this by installing rtl-sdr package
$sudo apt update $sudo apt install rtl-sdr
Run the test
#stop fr24feed first $sudo systemctl stop fr24feed
$rtl_test
Using device 0: Generic RTL2832U OEM
rtlsdr_read_reg failed with -7
rtlsdr_write_reg failed with -7
rtlsdr_read_reg failed with -7
rtlsdr_write_reg failed with -7
rtlsdr_read_reg failed with -7
If you get a similar out, you need to upgrade the Pi's firmware. Run the following command and reboot the pi after the upgrade is complete
$sudo rpi-update