As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RADIO TUNING PANEL SHOWS 'FAIL' IN BOTH WINDOWS WITH HF2 SELECTED. HF2 APPEARS TO WORK NORMALLY AND WHEN FREQUENCY TRANSFER SWITCH CYCLED, FREQUENCIES TEMPORARILY RETURN TO WINDOWS. GROUNDED - YES. PERFORMED BITE TEST PER B737-800 FIM 23-11 TASK 801 ON BOTH HF TRANSCEIVERS 1 AND 2, OPS CHK GOOD, NO FAULTS NOTED.