Firmware and forced updates over SIM

The car downloads firmware only over Wi-Fi

Half the myths about “forced updates over the SIM” come from one distinction:

• The notification about an available update arrives over the cellular connection: the built-in eSIM or your physical SIM. The car sees the new version and shows it on the screen and in the app.
• The firmware package itself is not downloaded over cellular. Wi-Fi or phone tethering is needed. The chat confirmed this repeatedly, including on a brand-new 2025 Model Y: #456091, #470086, #470169, #455960.

The typical newcomer's dead end: the SIM is in the MCU, music and YouTube play, and when offered an update the car answers “connect to Wi-Fi”, and the circle closes (#480093, #480097, #480099). The SIM is enough for streaming, not for an update.

Phone tethering works, but count the data: for one owner a single such update turned into a bill of 80 BYN (#480103). Maps should not be pulled over a phone at all (see the section on sizes).

What pulling the SIM actually achieves

The advice “pull the SIM so Tesla cannot force an update” does not work the way it promises:

• The car does not pull firmware over the SIM anyway, so there is nothing to block this way. The update will not move until you give it Wi-Fi, and that is the only real off switch.
• Without a connection you lose the app, notifications and remote commands, and the car stops being online for Tesla's servers.
• The “switch to an e-SIM instead of the SIM” option does not hold up: the eSIM is soldered into the modem and belongs to Tesla, and no third-party profile can be written to it. Details are in the article on the modem and SIM.

If the goal is to stay on a specific version, it is enough not to connect the car to Wi-Fi and not to tether internet to it. The SIM is best left in place: pulling it costs you the certificates and the app, and does nothing about updates.

Certificates: those actually live on the SIM

Certificates arrive over the cellular connection and weigh a couple of kilobytes, so they do not need Wi-Fi:

• a car with a SIM but no Wi-Fi will not get an update, while its certificates will be fine;
• a car with no connection at all loses both: certificates only renew on a car that is regularly online.

A separate recurring fear: a software update on a car with deployed airbags and fired pyrotechnics does not kill the certificates (#503438, #503441).

How to check the state of this pairing and assess the risk: certificates and linking to the app and the risk calculator.

How to keep the car on Wi-Fi

Working solutions from the chat:

• ScreenMate: it has its own SIM, shares Wi-Fi, the car is always online and downloads updates by itself (#466869).
• A router with a SIM and a 12 V battery in the garage (#470090).
• A router hung out of an apartment window works as a repeater for the car in the yard, tested from the 11th floor (#453853).
• A USB modem right in the car is not recommended by the chat: the car does not sleep, it eats the 12 V, and the Wi-Fi does not always reach (#463717).

To stop the car falling asleep in the middle of a long download, switch on Sentry Mode (#464805).

Updates not arriving for months: a checklist

1. Check that the car is actually on Wi-Fi, not merely “seeing the network”. Without Wi-Fi there is no point waiting (see the first section).
2. Change the internet exit point. One owner had 2025.32.6 hanging for two months on stable Wi-Fi; after tethering through a VPN the update arrived within a minute (#466076). Over Beltelecom Wi-Fi the updates did not come, through a VPN they started (#466070, #466072). Another case: from a Belarusian Wi-Fi the download breaks off at 75% and resets in a loop every day, while from an American IP it goes through straight away (#454466, #454468). The working combination is a VPN plus tethering from a laptop (#454470); not every VPN works. After the 2026.x builds landed, some cars started updating without a VPN too (#454474).
3. Software Reinstall in Service Mode: 5–10 minutes, the standard way to nudge the process along (#475885).
4. A full power-down of both batteries. For one owner neither the buttons nor the reinstall helped, but after a full shutdown and restart the update arrived within 10 minutes (#484474, #484547).
5. If nothing helped, the bootloader or the updater is stuck. At a shop the firmware gets “pushed”: as of September 2026 that is around $100 and 10–15 minutes, after which the updates come in a chain (#487710, #506384). Nobody gives guarantees: there is a case where, after a cheap $50 push, the firmware hung again and the owner had to pay a second time (#506387). The full recipe for unfreezing a car that had not updated for two years: clean the updater, do a “handshake” with the firmware, get an update push from Tesla Service plus a European VPN. After that both the firmware and the maps arrived (#456410, #456411).

Two common side stories:

• The car will not sleep and loses ~10% per day. The cause is a stuck endless update-request process, not the 12 V battery: one owner replaced the battery twice for nothing, and the problem went away when the car reset the process (#465603, #465613). The fix is to give it internet and let the download finish.
• “Software reinstall” is unavailable and there have been no notifications for six months (typical for 2024.44.4) while the certificates are alive and the app works. Without connecting a service computer you cannot tell the causes apart: either the firmware is downloading in the background or the request is stuck; on MCU1/Tegra connecting remotely is harder (#456412, #456413, #456421).

Hanging after an NA→EU region change

A mass story of summer 2026: after a region change, updates stop arriving on some cars, the typical stall being 2026.8.3 and 2025.32.x, on stable Wi-Fi (#484476, #484542). The chat argues about whether a region change can break anything (“there is nothing to break there”), but everyone knows the cars stuck on exactly that firmware. The order of actions is the same as in the checklist above: VPN → reinstall → full power-down → shop.

In autumn 2026 a second scenario was added: the navigation updates while the firmware hangs (for example on 2026.26.6.1) with Connectivity green and the app working. It is fixed by an update push at a shop, and some owners had to drive in twice (#502448, #506457).

How big an update is

• Firmware: hundreds of megabytes (#464640).
• EU maps 2026.8: 7.85 GB (7,924,469,824 bytes), downloading in anything from 30 minutes to several hours (#501886, #501297).
• Anomalies seen in the chat: 19 GB in three hours, and 150 GB+ that kept downloading in a loop until the owner did a reinstall (#501890, #465551).
• A known bug: the progress bar and the notifications disappear while the download continues in the background and eventually completes. Do not poke the car (#501901, #501907). There is no need to reboot the car after the maps install (#501892).

Region change and maps: what exactly gets changed at a shop

• The official route: the shop opens a title job, the map region and the account region are changed, and the maps arrive over the air (#506348).
• “Loading maps through a laptop console” is a different thing: such maps are not synchronised with the Tesla Cloud. By one specialist's observations, 9 out of 10 cars with a stuck updater have exactly these console-loaded EU maps, often EU 2019 (#506378, #506412). The link is not a hundred per cent, but badly installed maps really can kill both the updater and the certificate renewal (#506446).
• Maps after a region change do not reach everyone: from a week to several months; in the chat both 7 months and “you might be waiting 2 years” have been quoted (#475380, #464632). There were mass map rollouts in February 2026, and before that two years earlier (#475498).
• Prices, as of September 2026: a navigation region change, $50; a forced map load, around 250 BYN (other messages say $100–150); custom maps, $600–800 on top of the official $100/mo subscription (#508769, #508772, #484520).
• The catch with custom maps: the firmware can be updated, the maps cannot. The owner decides by hand whether to give Wi-Fi for a particular update, otherwise the custom set is lost (#503680, #503683). On some cars the maps freeze at 2019.20 forever after certificate restoration (#507100).

Is it worth updating

What fresh firmware fixes:

• Music. On stuck versions (2025.32.6, 2026.2.6, the February 2026 builds) Spotify starts for a couple of seconds and crashes, while YouTube Music and Apple Music hang in an endless load. The certificates are alive, the modem is green, the other apps work. The cause is a DRM update on Tesla's side, and only fresh firmware fixes it (#473644, #488001, #488003). The temporary workaround is a phone over Bluetooth (#488004).
• Grok in Belarus. It is tied to the geolocation the car takes from the installed maps: on an American car with NA maps it worked, and it disappeared after EU maps were loaded (#497919). In mid-September 2026 it was switched off for Belarus, and on 18–19.09, after the 2026.32.3 update, it started working again for many (#507831, #507843). Since 2026.26 Grok can control the car: it turns on the mirror and seat heaters and finds a track in Spotify and Apple Music (#494847, #508146).
• Battery preconditioning on navigation to a charger works automatically on fresh firmware.

What it breaks (read the chat reviews before installing):

• 2026.20: the car silently pulls data for a week (up to 150 GB), with no bar on the screen and no notifications in the app, while everything in Service Mode is green (#465551, #465553). Same build: the music keeps playing on the external speakers after the car is locked through the browser (#465557).
• The summer build: the left steering-wheel scroll wheel stops changing the music volume and adjusts the navigation volume instead. A reboot does not help. What helps is to plot a route and immediately end it; more reliably, mute the sound completely in the navigation tab (#502300, #502303, #502306).

What Tesla actually punishes you for

• A “soft” ban (as in Russia): the firmware simply does not arrive. It is fixed by changing the geolocation; there are no other restrictions (#503558).
• A hard ban for interfering with the CAN bus: Tesla forcibly changes the car's configuration and takes FSD/EAP away. Cases have been recorded in Europe (#503724, #503546).

In the first case you lose updates; in the second, features you paid for.

Imported cars: manual firmware and region change (tsk.by)

Some cars do not get updates at all. From the practice of a Minsk shop (tsk.by breakdown):

• Cars from the USA/China often do not get OTA automatically: there is no link to Tesla's servers for “their” region. In such cases the firmware is installed manually at the shop.
• Typical software failure symptoms: freezing, a cyclic reboot (boot loop), a black MCU screen. Usually after a failed update or a power failure during installation. Fixed by reinstalling the OS and reflashing the controllers.
• A software region change (USA/China → Europe) affects Supercharger access, maps, charging settings and some Autopilot features. Some settings may be reset to factory defaults in the process.
• Features physically present in the car can be unlocked in software: rear seat heating, steering wheel heating, washer nozzle heating, tow mode. The catch: large OTA updates can reset part of such a configuration, and the settings have to be applied again. Source: tsk.by

TESLA Belarus community experience

From the TESLA owner's group BELARUS chat: analysis of 400,000 messages.

Who raised the topic: Adrian, Ilya, Olya, Viktor

Who helped figure it out: SΞDΞK, firago, Nikolai

Discussion on Telegram: #70355, #156626, #355473

Links

• Modem and SIM: why the eSIM cannot be replaced
• Certificates and linking to the app
• Certificate risk calculator
• Tesla Software Updates (official): https://www.tesla.com/support/software-updates
• Why Is Tesla Forcing Software Updates? (InsideEVs): https://insideevs.com/news/400812/why-tesla-forcing-updates-safety-issue/