As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACCOMPLISHING T/C (N8234000 FMC NAV DATA UPDATE) FAILED LOAD. MESSAGE: DATA LOAD IN-OP, NDB MEMORY FAIL. WOULD NOT CROSSLOAD BACK TO #1 AFTER FAILED ATTEMPTS. GROUNDED - YES. REMOVED AND REPLACED #1 FMCS COMPUTER REF B737-900 AMM 34-61-02. ALL TEST PASS. GROUND VERIFICATION TEST SUCCESSFUL.