As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF1 TEST INOP PER FLT VERIFICATION. GROUNDED - YES. REMOVED AND REPLACED HF 1 REF B737-800 AMM 23-11-21. OPS CHECK GOOD. DURING REPLACEMENT FOUND A #10 BOLT 2 INCHES LONG ON THE BACK OF THE RACK THAT POSSIBLY IMPEDED THE TRANSCEIVER FROM PROPERLY MATING TO THE AIRINC CONNECTOR. ALL TESTS PASS.