As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ASH 6775 LAS. AIRCRAFT RETURNED TO GATE FOR FLAPS FAIL AT 8 DEGREES. MX FOUND THAT FAULT WAS DUE TO THE GPU NOT PROVIDING THE POWER REQUIRED TO OPERATE THE HYD PUMPS. MX SWAPPED GPU AND AIRCRACT OPS NORMAL. AIRCRAFT DEPARTED WITH NO FURTHER DEFECTS.