The start of the Bahrain Grand Prix at Sepang had to be delayed, and rain was not to blame. A substantial part of the delay went not toward waiting out the weather at all, but toward sending a software update to the teams: cars were stalling right on the formation lap, losing power and nearly coming to a halt. The federation’s wording was dry and careful — “an unforeseen combination of low engine speed, low-grip conditions, rain energy-management settings and the configuration of sectors at Sepang.” The technical department lifted the energy restriction in the troublesome areas, pushed a patch to every competitor, and frankly admitted that nobody had caught the glitch either in testing or on laps to the grid.
An ordinary technical note, one of dozens in a Formula 1 season. But behind it sticks out a detail fans rarely remember. Formula 1 rests on the fact that the cars in the field have almost nothing in common: each has its own engine, its own aerodynamics, its own carbon fiber, its own philosophy. And against that backdrop, there is exactly one piece of hardware that is identical for everyone and must not be touched. One computer, one firmware build for the entire paddock. When it stumbles, everyone stops at once — which is precisely what happened at Sepang.
Officially, this piece of hardware is called the Standard Electronic Control Unit, or SECU; in Russian, the simplest name is the standard electronic control unit. The word “standard” has a strict definition in federation documents: a part designed to FIA specifications but manufactured and supplied by a single producer. Elsewhere in the same regulations sits the category of “prescribed” parts — also made to specification, but permitted to be produced by several suppliers. The difference between those two lines is the whole story: the SECU is not merely a part made to a template, but a part with one and only one seller for the entire league.
This box has more work to do than any other component on the car. It controls the entire hybrid power unit, the gearbox, clutch and differential, along with adjustable aerodynamics, the braking system and tyre sensors. It also handles the energy-recovery system with its electric machines, and is connected to the crash-data recorder and the circuit’s marshal system. Everything in the cockpit that can be pressed or turned — settings, the choice of energy-deployment map, the temporary power-boost button — also lives within its permitted set of functions. Teams must register those maps with the federation before the race, and the federation can see from the telemetry exactly which map was active at every second.
Put simply, it is the only electronic box allowed to control the car. The rule is written without loopholes: no other electronic control systems may be fitted to an F1 car.
The company that makes the box has a long history. In 1989, Ron Dennis, then boss of the McLaren team, set up TAG Electronic Systems — someone in the paddock had understood before the rest that the real race was moving into electronics. Its first major contract was with Mercedes-Benz for its Group C sportscar prototype, the very car driven by a Michael Schumacher who had not yet made it to Formula 1.
After that, the company changed its sign several times without changing its essence: 2003 — McLaren Electronic Systems; 2014 — McLaren Applied Technologies, after two of the group’s technology subsidiaries merged; 2020 — simply McLaren Applied. In 2021, investment fund Greybull bought it from McLaren Group, and in 2025 it officially cut the cord and became Motion Applied. It now describes itself as an independent Tier 1 supplier, and said exactly one thing about McLaren in its press release — that it “will always be part of our history.”
The current unit is called the TAG-320B. On the outside, it is a brick-shaped box weighing close to 1.5 kilograms, sealed in black anodized aluminum, with Lemo connectors designed for vibrations from 100 to 1,000 hertz. Inside are 32-bit processors, storage for nearly eight gigabytes of logs, up to eleven CAN buses, a FlexRay channel, an integrated three-axis accelerometer, and internals rated for no more than 70 degrees. Its application code is not written by hand: it is generated automatically from MATLAB/Simulink models, the very engineering software used to model aircraft. Its performance is measured in the CoreMark benchmark — around sixteen thousand units in the current version. It does not impress with raw power; it impresses with the demands placed on the exact instant it must respond.
To understand where this uniformity came from, you have to go back to the mid-2000s. The federation’s president at the time, Max Mosley, spent three years pushing the idea of a standard unit, with three goals at once at the top of the agenda: cut team spending, eliminate driver aids such as traction control, and finally obtain a tool with which the federation could monitor engine use and test mileage. Betting on one box solved all three at once.
The 2006 tender looked more serious than some government contracts. The winner undertook to supply an unlimited number of units at a fixed per-unit price set for every team, bear the full burden of R&D, including changes imposed later by the regulations, and maintain trackside support for nineteen races and five tests per season. But the most telling condition was financial: a bank guarantee of at least one hundred million euros in favor of the federation, which it could call in without argument if the product proved faulty or deliveries failed. A hundred million in collateral for the right to put a box in every car in the field.
The contract went to a joint bid from McLaren Electronic Systems and Microsoft. Microsoft added Windows Vista, SQL Server, and a brand name the federation clearly liked; there were even rumors that the choice had been driven less by quality than by price and that very name. Teams were promised substantial savings: a full set of units and sensors for one car cost them “tens of thousands of pounds” — according to a supplier representative, less than half what it had cost them to make their own. For people spending millions on engines and aerodynamics, it was almost invisible money.
But there was an awkward fact that received plenty of coverage at the time. McLaren Electronic Systems belonged to McLaren Group — the same corporation as the McLaren team, a direct rival on track. Ferrari and Renault, whose cars ran Italian Magneti Marelli systems, considered that unfair: the supplier of the common unit necessarily knew its workings better than anyone else. The federation pushed back by citing openness: teams were shown the source code of the control applications. And, just in case, the tender document for 2026–2030 retained a safeguard — if the tender were won by an organization directly or indirectly involved in the championship, the federation reserved the right to “take measures to ensure compliance with the principles of sporting equality.” It seems lessons were drawn from that scandal, but not enough to exclude anyone.
This is where it gets most interesting for anyone who has ever messed around with firmware. The rules state it flatly: there is only one version of the software approved by the federation, and a team may not alter it. Then there is a requirement that would sound absurd in consumer electronics but sits at the top of the list in F1 — “a reliable means of ensuring that all software within the ECU is identical to that which has been inspected and approved.” In other words, it is not just about stopping anyone from cheating. It is about making sure that twenty units carry the exact same firmware down to the final byte.
They achieve this through several methods. Every programmable device must have a mechanism that unequivocally identifies the software version — even secure hashing with an added random string issued by the federation itself will do. In a separate clause, the supplier is forbidden from embedding “fuses” and other locks that might prevent stored firmware images from being extracted. The code for standard applications is handed over to the federation, every new version must receive its approval before release, and the interface requirements stipulate that any third-party unit may connect only through an open protocol or open standard. The irony is that the component which looks most closed-off on the car has turned out to be perhaps the most transparent — at least to those with access.
The same logic produced a “common language.” Teams model control algorithms in Simulink, and the unit turns the model into finished code. One compiler, one set of libraries, one set of APIs, one computing platform — the federation wanted to compare cars by engineering thought, not by who had the better software drivers. That is the price of fairness: instead of independent implementations, each with its own backup circuits, the league has one.
Now we can return to that scene. The cars set off on the formation lap in the rain, the safety car was crawling along, Max Verstappen, running ahead, sharply reduced his speed, and an accordion effect rolled through the line: each following car braked harder than the previous one, and several nearly stopped. The cars passed some of the circuit’s mini-sectors at speeds never factored into the calculations at all. And then the box showed what it was worth.
The federation’s director of single-seater series, Nikolas Tombazis, explained it plainly: a bug in the software meant that once a car entered this mode, it fell into a loop — it could not lift the power restriction and accelerate again. This was not software written on someone’s knee in a garage. The federation and the teams had developed it together for years, and it had been tested by Red Bull and Racing Bulls among others. One thing was missing: there had been almost no wet testing this year, and nobody had remotely run the unit at the speeds that occur only behind a safety car.
The emergency solution was rough and fast. The energy restriction tied to the 250-kilowatt ceiling was simply removed in the problematic mini-sectors. By Tombazis’s own admission, the patch was “not ideal work” and had not been tested at all: there were neither five days nor even an hour for a proper check — only a few minutes while the track dried. The logic of that decision is questionable as a precedent, but that evening it saved the race, and the federation preferred to lose precision rather than the schedule.
One more detail says a great deal about the new regulations. By early estimates, the bug was routing the entire accelerator-pedal signal into charging the MGU-K electric machine. Drivers pressed the pedal and got nothing at all — from the outside, it looked like a stalled engine. The internal-combustion engine was affected too, even though at those revs it seemingly should not have been; the federation has no formal answer yet for why that happened. And Tombazis disposed of fans’ favorite question — why cars with Mercedes engines suffered less — without any intrigue: there was no technical reason, merely different speeds in different parts of the queue.
The paddock’s response ranged from zero to a thousand. The drivers were angriest of all: Fernando Alonso pointed out that he himself had retired from half the races that season, and none of them had been stopped because of it. Mercedes boss Toto Wolff called Sunday one of the worst experiences of his career. Deputy team principal Bradley Lord spoke more calmly and to the point: the cars and the regulations, he said, are “damn complicated,” and even in the fifteenth or sixteenth race of the season they are still being caught by surprise — which means the broad direction should be not toward greater complexity, but simplification. Tombazis chose a different defense at the press conference: “I don’t know any software without bugs and updates — your computer probably updates every three days.” Formally, true. In substance, an admission that the track runs not only on engineering, but on indulgence.
It is funny that for the same purpose — to ensure that the outcome of competition is decided by skill, not ingenuity in getting around the rules — Formula 1 keeps tightening the screws on prescribed parts, balance of performance, and component standardization. The SECU was the first sign of this policy, and for twenty years it made the championship dependent on a single computer. At the time, it looked elegant: the federation gained both a lever of control and permanent access to data from every car, the teams gained savings, and viewers gained hope that aids like traction control could no longer be hidden in the code.
The price of that elegance was revealed not in the regulations, but at Sepang. One common unit means one common failure. In an ordinary car, overlapping systems are responsible for a loss of power control — one breaks, another keeps working, and you learn about it from a log rather than from a stopped line of cars. But when standardization reduces different teams to the same code in the same place, the very notion of a reserve disappears: a common component has no second copy, because a second copy means two suppliers and two behaviors. And behavior, as it turned out, matters if everyone is to remain equal.
The supplier takes such stories philosophically — and backs that philosophy with a number. When extending the contract through 2030, its management proudly announced that since 2008 the unit had accumulated more than 1.5 million racing kilometers without a single registered failure during a race. Against that statistic, Sepang’s autumn looks almost like a curiosity, and in its own way that logic is sound: a system built over twenty years did not fall apart — it stumbled once over a scenario nobody had anticipated.
But the answer to the question posed by the hook does not depend on the number. A shared part is not a guarantee that everyone is equal over the distance; it is a guarantee that everyone will stumble at the same moment. At Sepang, that cost an hour and a half in the rain and one patched mini-sector. Next time, the common box may hit another such overlooked corner — and then the federation will have exactly the same choice: lift the restriction, send out a patch, and hope nobody spends the few minutes allotted for code changes on talking. Twenty years of common firmware have taught the league precisely that — to fix quickly what cannot be changed separately.