As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL380 LT ENG LOST 50% POWER & SLIGHT VIBRATION OCCURRED, REDUCED TO IDLE. NO FURTHER VIBRATION OR ABNORMAL INDICATIONS, DECIDED TO OPERATE AT IDLE DECLARED EMER & DIVERTED. SUSPECT NR 4 BEARING FAILURE ON NR 1 ENG. R & R NR 1 ENG IAW WC 29-7100-1-0900, & 29-7100-1-4900. ALL OPERATIONS & LEAK CHECKS PASSED SEE LOG 2158623 FOR ROTABLE PARTS CHANGE, & LOG 8545596 FOR ETOPS VERIFICATION FLIGHT.