Following the conclusion of a detailed report into the finish to last year's season finale, motor racing's governing body published its conclusions on Saturday.
As well as revealing an executive summary of its investigation, the FIA's World Motor Sport Council also endorsed its key findings, which suggested that the fault for what went wrong was prompted by poor regulations and procedural errors rather than any deliberate malice from Masi.
Key to the situation were Articles 48.12 and 48.13 of the F1 Sporting Regulations which detail the process of backmarkers unlapping themselves and the timing of a restart.
In its conclusions, the FIA said: "It was apparent from the analysis that there could be different interpretations of Article 48.12 and Article 48.13 of the Formula 1 Sporting Regulations, and that this likely contributed to the applied procedure.
"It was also considered that the decisions regarding the Safety Car at the end of the 2021 Abu Dhabi Grand Prix likely took into account previous discussions that made clear the Formula 1 Stakeholders (FIA, Formula 1, Teams and Drivers) preference to end races under green flag racing conditions, rather than behind a safety car, when safe to do so.
"In combination with the objective to finish under green flag racing conditions applied throughout the 2021 season, the report finds that the Race Director was acting in good faith and to the best of his knowledge given the difficult circumstances, particularly acknowledging the significant time constraints for decisions to be made and the immense pressure being applied by the teams."
While the mistakes made in Abu Dhabi have prompted calls for the results of the race to be overturned, the FIA is clear that the matter is now firmly closed.
It added: "The results of the 2021 Abu Dhabi Grand Prix and the FIA Formula One World Championship are valid, final and cannot now be changed.
"In accordance with the rules, Mercedes made a protest to the stewards after the race, seeking to change the race classification. The stewards dismissed the protest and Mercedes then had an opportunity to appeal that decision to the FIA International Court of Appeal, but did not do so.
"There are no other available mechanisms in the rules for amending the race classification."
The FIA has replaced Masi for the 2022 season and made further changes to its procedures.
This now includes the process of informing which backmarkers can overtake being automated.
"The process of identifying lapped cars has up until now been a manual one and human error lead to the fact that not all cars were allowed to un-lap themselves," added the FIA.
"Due to the fact that manual interventions generally carry a higher risk of human error, software has been developed that will, from now on, automate the communication of the list of cars that must un-lap themselves.
"In addition, the 2022 Formula 1 Sporting Regulations have been recently updated to clarify that "all" and not "any" cars must be permitted to un-lap themselves."
