sudo journalctl --no-pager -u dump978-fa
sudo rtl_test
That’s actually the wrong place to configure that on a piaware sd-card image.
This is where you put the serials on the piaware image:
sudo piaware-config rtlsdr-device-index 00001090
sudo piaware-config uat-sdr-device driver=rtlsdr,serial=00000978
It’s all described here: How to Install and Configure Piaware 5.0 SD card image - Quickstart Guide