Over on Medium, Jugy depin has shared a useful troubleshooting write-up describing how they recovered a frozen RTL-SDR on a remote Raspberry Pi station located 700 km away, with no physical access available. The dongle had stopped responding with  usb_claim_interface error -6 and Failed to open rtlsdr device #0 errors, while still showing up in lsusb.

After ruling out the usual suspects, such as DVB drivers, conflicting processes, permissions, and even a full reboot, they concluded that the RTL2832U had locked up at the USB hardware level. To make things worse, they discovered that a Raspberry Pi reboot from the terminal does not actually power-cycle its USB ports.

The fix was to use uhubctl to cut and restore power to only the specific port the SDR was plugged into, after first carefully identifying which port that was (so as not to accidentally kill the Ethernet port and lose remote access entirely). The commands shown in the post performed a true hardware-level reset equivalent to unplugging and replugging the dongle, and rtl_test confirmed the device came back cleanly.

Jugy recommends that anyone running remote SDR stations either build uhubctl into a healthcheck script or add a smart plug for unattended recovery.