Formula One has made its debut in Azerbaijan with some immediate teething problems and Mercedes's triple world champion Lewis Hamilton fastest in practice around the Baku street circuit.
Australian Daniel Ricciardo brought out the red flags to halt Saturday's first session with 22 minutes remaining after he clouted a barrier, the impact ripping off his Red Bull's rear right wheel.
Race director Charlie Whiting and officials spent time between sessions fixing kerbs on the anti-clockwise layout that circles the medieval city's walls and runs along the Caspian sea shore.
Qualifying for the GP2 support series was postponed and Formula One drivers were instructed to steer clear of the kerb at the exit to turn six.
Television footage had shown the edges lifting as cars went over it.
"Some small bolts had come loose at the end of the kerbs on turns six and 12, so we've taken the bolts out and welded the kerbs to each other," Whiting told Sky Sports.