We're past that half-hour mark, meaning the teams have handed back that extra set of PIrelli tyres.
This is an interesting one.
Is Hamilton planning to challenge the one-helmet rule this season? He was definitely wearing his predominantly white "Still I Rise" lid he won the title with last year, but this could be a helmet he plans to wear later in the weekend.
Hamilton to Mercedes: "There was a click in the rear. The gears still worked."
Seems the team advised him to stop to preserve a race engine. Better to be safe than sorry.
@Rezillo: Nope. Can't imagine it'll be much more than a fine.
Hamilton also told Mercedes he could have made it back. Race engineer Peter Bonnington said because he has no telemetry they didn't want to risk him driving back to the pit lane.
@mfbull: Vettel suggested in the winter he'd be happy to keep breaking the rules if the money went to charity, but no-one is sure. Vettel seems pretty set on his current design though.
Hamilton's Mercedes has returned to the pits on a flatbed truck.
It's all a bit dull out there with no drivers out on track.
Stevens is back out on track in the #28 Manor Marussia.
Button has joined Stevens out on track.
The action is so thrilling Lotus is tweeting pictures of feet and legs.
@Rezillo: I think, for most people, the comments seemed a bit hypocritical. I think he raised some interesting points but a lot of people immediately criticised him for sour grapes.
@marty: Sauber have Raffaele Marciello, a Ferrari junior and their own test driver, in the car for FP1. Nasr gets the car back in the next session.
Button's latest lap puts him into 12th. I'm waiting for a good picture, but McLaren have added an S-Duct to their car this weekend.
Stevens is currently seven seconds down on Rosberg but I doubt we've seen a flat-out lap from the Manor Marussia driver yet.
Alonso starts a new timed lap. He's currently 4.5s down on Rosberg.
Seven drivers on track as it starts to get busier.
Alonso's latest lap is some 14 seconds down. That isn't representative of course, it's unlikely McLaren is running fully today as it still tries to get to grips with that Honda power unit.