As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF ROLL FUEL 2 LOW LEVEL CAUTION/WARNING DISPLAYED. ON TAXI BACK FUEL 2 LOW LEVEL WARNING DISPLAYED AND FUEL QTY 1 SHOWED DASHES. AT GATE FUEL IMBALANCE EICAS AND QTY FOR THE NO.1 TANK SHOWS 0. AFTER SLAVING IN NEW FCU MESSAGE CLEARED ONCE ORIGINAL FCU WAS REINSTALLED. R/R FCU IAW 28-41-01. OPS CHECK GOOD OK FOR SERVICE AT THIS TIME R/R FCU FOR MX CONVIENENCE.