Pat Fry was left frustrated after a "small but tricky problem" curtailed Kimi Raikkonen's running in Bahrain.
Replacing Fernando Alonso for the final two days at the Sakhir circuit, the Finn managed just 12 laps on Friday morning before a telemetry problem sent him into the pits.
Returned to the action later in the day, adding another 32 laps to his tally and setting a best time of 1:37.476.
"It was a bit frustrating, because we were stopped for quite a time with a small but tricky problem," said Ferrari director of engineering Pat Fry.
"We knew that sooner or later we would have to deal with some problems and that was what happened.
"These things happen with a new car; some things that seem difficult turn out to be easy and others that appear simple get more complicated and we are still learning."
He added: "We will try to do our utmost to acquire the mass of data we want. Ideally, we don't want to change our operational plan for next week's test."
And although Raikkonen's time on Friday was 3.213s short of Lewis Hamilton's pace-setting lap time, Fry insists there's little to be read from the times.
"It's hard to say where we are. We knew we'd be facing a very complicated winter with a lot of unknown factors.
"That was the case, but in Maranello we have done a lot of work and I can see that it's difficult for everyone to move forward on the development front with so many new systems and so little time to test them."