Marc Marquez says his Honda team is still not on top of the new engine software MotoGP will use during the 2016 season.
MotoGP will have a standard electronics control unit for all teams from the start of next year, a move that Honda was against before it was introduced.
Honda took to the track for a three-day test at Jerez on Wednesday, and Marquez described the electronics as a step behind compared to the bespoke software ran this year.
"The electronics are still not consistent," said Marquez. "We have made progress, but it's clear they are certainly a step behind the Honda software we are used to.
"But we know it won't be the same so we must find a way to work with it, especially concerning the engine brake and traction control."
He added: "Every time we go on track it's interesting because we try many things, starting with the software as our reference and with the Michelin tyres which is a big task to understand where the limit is.
"We did a few laps to understand a few things and we tried the new engine too which felt similar to Valencia but we must complete more laps to get the electronics working better, as it's hard to understand the true character until we have that fixed."
Teammate Dani Pedrosa suffered a crash near the end of the session, but was nonetheless happy with his work.
"It's been a good first day, despite the crash at the end where I was a little strong on the braking and lost the front in the last corner," he said.
"I was a little slower today as I've not ridden here since the 2014 race, so I took my time to adjust to the Michelin tyres and this bike at this track.
"I was comparing the different engines but also working on settings as I had no data from the race this year.
"We tried to do the best job possible today, for sure it was more of a setup day, tomorrow we will work on the engines, tyres and electronics in more detail."