Formula 1 bosses have backtracked on a ban on teams giving drivers advice over the radio.
Governing body the FIA has responded to teams' concerns that the ban would have cost and reliability implications.
Messages about the operations of an F1 car's complex systems will be allowed for the rest of the season.
But teams will still be forbidden from giving driving advice, such as how to improve cornering technique, via radio. The full ban will now start in 2015.
On Thursday, F1 boss Bernie Ecclestone had said he was behind the ban, saying he felt drivers were being helped too much.
But his claims that all the drivers were supportive of the idea were undermined when some, including Williams's Felipe Massa, expressed vociferous opposition.
And the teams argued to race director Charlie Whiting that the proposed ban could lead to reliability and even safety problems.
The FIA has provided to BBC Sport the list of radio messages that are permitted and banned.
|Among those still banned are:|
|Cornering speeds compared to another driver, driving lines and use of kerbs|
|Gear selection compared to another driver|
|Braking points and anything to do with the application of the brakes and throttle|
|Car set-up parameters|
|Use of the DRS overtaking aid|
|Anything to do with driving technique|
The FIA's note clarifying the ruling with the teams said: "It seems to us that information being passed to the driver concerning the performance of his car should be separated from information concerning his own performance.
"It has become clear that the former is a very complex matter and that any list of restrictions imposed at short notice will have a significantly different effect from team-to-team. The latter information on the other hand can be considered simple driver coaching.
"With this in mind we propose to postpone enforcement of the information being passed to driver concerning the performance of his car until 2015.
"We believe this will give sufficient time for teams to prepare properly and, more importantly, to ensure that the regulations are being enforced fairly and equitably.
"On the other hand, information being passed to the driver concerning his own performance will be stopped with immediate effect."
Whiting said the ban on radio messages had not been intended as a precursor to banning all telemetry, as Ecclestone had suggested on Thursday.
"That hasn't been discussed at all," Whiting said.
He added that he expected any punishment for transgressing to be "sporting rather than financial" and while pointing out that the stewards decided penalties, he gave examples of a drop of a grid position if the offence was in practice or a five-second penalty if in the race.